I think I've installed it correctly, but I can't get sound. (PC)
Go to Start>Control Panel and open Sounds and Audio Devices. Click on Audio and verify you've selected iMic USB audio system under sound Playback. Be sure you have your computer's internal speakers selected as your output, or playback device. If you're having problems recording, also verify you've selected the iMic under Sound Recording.
If you're still not getting sound, go to Start> Programs>Accessories>Entertainment and open Sound Recorder. Choose New under File, click the red Record button and speak into your microphone. You should see the green line move in Sound Recorder (actually, the representation of the waveform). Click on Play and listen to what you've recorded. You can also double check your audio settings by going to Audio Properties under Edit.
At this point, you've verified the iMic is working. If you're having further problems, check your software manual or contact the manufacturer.