Your OGG files will work, only on the V3 alphas, but the V3 alphas are unstable.

2.0 final is the best stable release. There is also Hijack, a very nifty kernel replacement that adds a bunch of great features, and Emphatic, an application that lets you customize the display, as well as letting you scroll song lyrics (only with a proper SYLT tag on an MP3 file).