Here’s a handy tip for creating custom colored buttons on the fly for your iPhone interface: don’t make them buttons at all, make them single segmented UISegmentedControls, and muck with the “tintColor” property. Ooh, shiny!
And hey, there’s something you can apply that nifty color picker we mentioned to have your users customize your color scheme on the fly. Oh, the sartorial possibilities just stagger the imagination, don’t they?
[EDIT: Since UISegmentedControls don't work quite like buttons, following this tip will make your UI just that little bit off. But here is a much better way to make your buttons shiny!]