Hello. I'm new to the forum and wanted to introduce myself. My name is Adam DiTroia and I'm a composer and sound designer for games and other media. I recently created a company dedicated to mobile games. It's called "Mobile Audio Design" (or M.A.D. for short). More info about me can be found at www.adamditroia.com.
I also wanted to start out by contributing in at least a small way. So here are a few tips/tricks for creating great music and sound effects for mobile games and apps:
1. Mobile devices (iPhone, iPad, Droid, etc) lack bass response. So my first tip to you is forget the earth shattering sub-basses and low, deep synths. They will simply disappear when implemented into the game. Try experimenting with different EQ settings and always play the music track or sound effect back on as many mobile devices as possible (as well as earbuds/headphones).
2. While mobile game sizes are increasing (in some cases they're as large as 2 gig or more), audio is still treated as the last kid picked in dodgeball sometimes! So like it or not, you're going to have to compromise. I'm typically asked for mp3 for music. One thing you can do is chose a bitrate that is a good compromise between size and quality. 128 seems to work well. But check with the developer first of course.
3. This last tip has to do with creating a smooth music loop. For some reason, when saving as an mp3 in Sound Forge, there is always extra space added to the front and end of the track. My final step before sending it to the developer is opening it in Audacity (which is free) and trimming the ends. Why Audacity does this and not a much more expensive program (Sound Forge)...I have no clue :)
I hope you find these tips useful! Thanks.