I know you guys make computer backgrounds so why not get into some phone ones? IF you would like say your down i guess?? ill look up dimension of some phone wallpapers later
i believe http://www.interfacelift.com lets you download free phone wallpapers. Just click on the image you want and check out the options it gives you. some of them you can, some you cant. and if you can't get that to work, the site still makes great desktop/laptop wallpapers!
Get Adobe Photoshop and make your own. Just start out with a canvas the size of your resolution. I make many of them for my Blackjack.