USB plug and play on Angstrom

Current problem:
USB is detected if it is plugged in during board boot -up but unable
to mount it after OS has booted. Also please suggest means to run
applications at start up.

Details:

I am a beginner with the beagle board and trying to write a media
application that directly reads mp3 files from a usb stick and play
it. I also aim to interface a 4*16 LCD display to show the list of
available tracks and to interface the keyboard to browse through the
tracks. kindly provide guidance as to what references i must use in
order.

yours sincerely,
G. Varun