Gain settings are the way to go if you just stick to the default recording application.
Or there is
Resco Audio Recorder (works after you install then soft reset - no documentation, but has VAS and can adjust the mic sensitivity) or
NoteM (this one's free but no VAS slider) which can both record in MP3 giving you much more space available for recording.
I used my Pocket PC in my last recurrent class to record what questions to study for the test the next day. Worked great!
VAS is awesome for that type of environment too.