If you like information about the M-Audio Transit and Linux, here is some: http://www.theory.physics.ubc.ca/transit.html. I cannot say anything first hand about the M-Audio Transit. The Behringer UCA202 is probably less of a hassle to run under Linux and lets you monitor the source and/or output with a headphone output, which works great with my ATH M-50 studio monitor headphones.
Markus