I would prefer that your submissions be 100% vector (Illustrator CS3 format preferably), but I don't want to hinder your creativity. I'm well aware that there are certain tricks that just can't be done in a pure vector manner. So, if your design needs raster elements, so be it. Just make sure to keep it big. There are two sizes that will be sent to Apple: the app icon itself is 57x57 in png format, and the icon that shows up in iTunes is 512x512 in tiff format. I'll rip the final files from your master, but just make sure that, if you have any raster elements in your master, to keep it at or above 512x512.
Re: Icon content... Like I said before about the competition: their icons all look more or less the same and none of them are very engaging. They do tell the story, but they all look kind of flat and lackluster. I really need to stand out in this fray. I need the icon to sizzle. I want people to see all 10 of us lined up like ducks in the App Store and for them to be compelled to click on my app first.
There is an old Mac icon I love by a designer I worked with a few years ago named Matthew Bice ( http://www.iheartny.com/ ). It's called "robot" and is part of his "Soda Jerks" icon collection. It's an "Iron Giant" sort of thing. Try, if you can, to draw some inspiration from that icon (screenshot attached). ... but any and all ideas are welcome!
(Please, no stock art. Original illustrations only.)