Converting Apple Lossless to 320kbps

Last year I spent a lot of time ripping all my cd's onto my laptop using Apple Lossless. The main reason I wanted to do this was so that I could listen to my music at full quality using my SqueezeBox. I'm heading to medical school, and am not taking my sound system with me. I'll have just my iPod, and lossless quality songs drain the battery too quickly and use up a lot of space.

Can I take my lossless songs on iTunes and convert them to ~320kbps? I would really rather not have to import all my cd's again.