Thinking about making wallpaper for the Droid? Nothing tough about it. Just make an image that is 960x854, but make sure that the main focus of the image is no wider then 480. This will let you see everything on the main screen and it will scroll and scale nicely. You probably have to see the implementation to understand what I mean, but it works, trust me!
I've attached a simple New Orleans Saints wallpaper I created. I like the solid colors so you can see the background and you can arrange your icons to make the logo visible. Like everything else, you need to play around a bit to make it work for you, but at least this will show you a starting point!
Reebok used the above logo on Katrina Relief gear that it sold after the hurricane. I believe all the profits went to help the city of New Orleans. I am putting this here so I don't get hit with a copyright violation or something like that. I just love the logo!