If you feel like the Windows Mobile interface is in need of a little sparkle then you Should consider installing LimeLine.
This free Pocket PC theme brushes stardust all over your screen, adding a striking blue and gold background wallpaper to your display. Sparks and light flares help to make this a truly stand-out image.
Although the wallpaper looks great, I felt the choice of green as the menu bar color didn't really compliment the background. I'm a firm believer in the old adage 'blue and green should never be seen, unless there's a color in between'. In the case of LimeLine there is no color in between, so it's a bit too garish in my opinion.
But if you want a way of brightening up your Pocket PC, LimeLine will certainly make your display more eye-catching.