Microphone capabilities?

Type in MIC and look at the suggested commands. Or better yet, there's a manual to read.

http://smilebasic.com/en/reference/#input If you don't have a problem working with wave input.

Here's the only example of a game that uses the microphone that I can think of. http://smilebasicsource.com/page?pid=70&cid=991 Petit Modem uses it also, but It's a really complicated program to look through I'm sure.