Good to know. You should encode it in Ogg Vorbis format rather than (or as well as?) MP3. Apparently you get more "bang" (quality) for your "buck" (file size).
As for Shada, they haven't tried to make it slot into the appropriate place in the Tom Baker era. They have a little prolouge showing how the 8th Doctor manages to meet up with Romana and K9 again, then they handily go back in time to resume some aborted mission 30 years earlier. They do refer to some Tom Baker event, but it's not going to ruin your enjoyment or anything.
It's also available in RealAudio format, which despite being evil, does have the advantage of being able to scale itself to almost any connection, so you shouldn't have much trouble listening. (If you don't have RealPlayer installed, make sure you grab RealPlayer 8 from somewhere rather than the spyware-tastic RealOne).
Oh you do go on, Huz.