Just dug this out.
End result:
1. Start out by opening a new document. I used 400x150, I'd recommend something like that or larger, but you can do it smaller if you like.
2. Find your render (main image). Cut it out (I use the polygonal lassoo with a 2px feather) and paste it onto the document. Now get the eyedropper tool and choose two prominent colours for your foreground and background colours. As I was doing a Barcelona sig I chose the red and blue on the shirts. When you've chosen the colours make the render invisible (click the eye inside a square on the layers list).
3. Now make a left to right gradient with those two colours. Then go to Filter - Distort - Wave and do this a few times, so the colours mix.
4. Go to Filter - Pixelate - Mosaic and choose a cell size of between 20 and 30. Click OK.
5. Now go to Filter - Sharpen - Sharpen, and use this two or three times. You should now have something like this:
http://img201.imageshack.us/img201/1959/mosaicua1.png
6. Now duplicate that mosaic layer (Ctrl J) and go to Filter - Pixelate - Mosaic once more. Change the cell size to something between 60 and 80, depending on your canvas size. You should only have about eight cells visible on your canvas.
7. Now hide the bottom mosaic layer and duplicate the bigger mosaic three times. Now, on the first big mosaic layer cut out some of the squares. For example, you could cut the four top left cells, but leave the three top right, or whatever. Here's a screenie (with the original mosaic hidden):
http://img237.imageshack.us/img237/4...tmosaicce5.png
If you have a white background that doesn't matter. Set this layer to 70% opacity.
8. Now on the two duplicated layers, cut out one square on each. Try to choose a square that's coming across some of the squares on the bottom large mosaic layer. Cut out a square for each layer and set the blending mode to soft light, with the opacity on 80%.
http://img237.imageshack.us/img237/7616/so...htmosaiczb1.png
9. You can now make the bottom, smaller cell size mosaic layer visible.
10. Make a new layer on top of the mosaic layers but underneath the invisible render. Now fill it with a pattern, I used diagonal scanlines. Set the pattern to soft light, and 50% opacity.
http://img237.imageshack.us/img237/7...anlinesys3.png
11. Now it's time to get out some brushes. Make a new layer and use some lighting brushes. If you don't have any of these go to
www.deviantart.com and search for some; I have a really nice pack called
nightsky. If you want, you could probably use a different type of brush, so long as you do it in white.
12. Brush lightly over the background. Then set this layer to 70% opacity.
http://img237.imageshack.us/img237/2540/ni...brushingqf5.png
13. Now make a new layer and do some more brushing. This time do less of it, but try and make the brush tips larger. If you look on the previous screenshot, you can see some wider 'stars'. Try and focus on those. Set this layer to soft light.
http://img237.imageshack.us/img237/19/2ndn...brushingva2.png
14. Now use the rectangular marquee tool (the box with dotted lines) and at the top, iin the 'style' dropdown menu, change the setting to 'Fixed Size'. Enter 30px as a width and whatever your canvas height is as the height setting. Mine was 150px.
15. Now click on the canvas, try and start on the left, and fill the selection with white. Now duplicate the layer with one rectangle and move the rectangle across. Keep doing this until you have gone across your canvas, with gaps in between rectangles obviously.
16. Now merge all of these rectangle layers (Ctrl E). Set the blending mode to 'soft light' and opacity to 50%.
http://img237.imageshack.us/img237/9624/wh...ctanglesfa0.png
17. Now duplicate this layer and move the rectangles over slightly, so the still overlap, but only just. Set this layer to soft light, with 30% opacity.
http://img237.imageshack.us/img237/2296/do...ctanglesra5.png
18. Now right click on the brush tool, and a dropdown menu should appear. Pick the pencil tool. Make sure your foreground colour is white, and then, holding shift so the lines are straight, draw down the canvas. Try and vary the gaps between lines. Set this layer to about 70% opacity and soft light.
http://img237.imageshack.us/img237/9...illinesrs3.png
19. Now get the shape tool and do a few shapes around the canvas. I used rounded rectangles and circles, don't do too many, I did three rectangles and four circles I think. Set the shapes to soft light and opacity 30%.
http://img222.imageshack.us/img222/3810/shapesdx0.png
20. Now add some faded in, large text. I used a size of about 100 and put in 'barca' and 'champions' since I made it for a graphic battle and the theme was Champions League. Set it to soft light, 30% opacity if you have a darker background, or just 30% opacity for a lighter background.
http://img201.imageshack.us/img201/7691/la...etteringlz3.png
21. Now the background's looking pretty good. It's time for the finishing touches. I pasted in a Barcelona logo. You can either resize it so all of it is visible or keep it larger than the canvas and choose a prominent figure in the logo, for example if you were doing Man Utd you could use the devil. Set this to soft light, and whatever opacity you think looks best. I usually use around 70%.
http://img222.imageshack.us/img222/9195/logoab1.png
22. Now add text. Please don't use Times New Roman like me, it's completely uncreative and looking at it a second time I don't have a clue why I used it.
http://img201.imageshack.us/img201/2513/textgu9.png
23. Now it's time for the render. Make it visible again and duplicate it seven or eight times. Give the bottom layer a Gaussian Blur, (Filter - Blur - Gaussian Blur) of between 6 to 13 pixels.
24. Ok, now we add the snazzy smudging. This part is optional. Also, credit to Michael from SoccerDesigns for adding this tutorial on there, so I better post a link.
http://www.soccerdesigns.co.uk/forums/inde...?showtopic=3886
25. Follow that to create the smudge brush as I can't be bothered to type it all out. Then, on the layer above the gaussian blur, and the top one or two layers (up to you), use the smudging brush on the player's shirt. Then sharpen this layer two or three times and set it to pin light. Erase any smudging on the face.
26. Now for the render effects. Here's what I usually do: put a smart blur of 15 and 20 (low quality) on the bottom layer (above the gaussian blur and first smudging layers though). Then I set the next layer to overlay, and the final layer to screen or hard light, whatever you think looks best. Delete the remaining render layers.
27. Now just add a border. I used a 7px white border first, set to center, and then on a new layer, a 1px black border set to outside. It's up to you though.
Here's the finished product once more:
Please post any results you get in here, I like to see what people make. Cheers.