Hi Oliver,
first, rumor has it FLAC sounds a bit better than Apple Lossless.
I'm not totally convinced that I can hear a difference between FLAC and Apple Lossless. They are both lossless, but perhaps there is something going on in SW that may explain why people hear a difference (iPod's stock SW vs Rockbox).
if I've already ripped a lot of my music in Apple lossless, do I have to go back and rerip it in FLAC?
RockBox is compatible with Apple Lossless, FLAC, and many others. If you want your files to be converted to FLAC, you have to convert them. I'm not sure if there is automated SW out there that will convert from Apple Lossless to FLAC for you..
Does rockbox affect the iTunes software itself, or just the iPod?
Itunes is not changed, but the SW on your iPod is changed. After RockBox, you will essentially treat your iPod like a USB hard drive. You make a music folder and copy and paste your music files into it. I don't think you'll be using iTunes when you use Rockbox, but I may be wrong.
There have been Rockbox updates since I tried it a while back, so it is best to get all the gory details here:
http://www.rockbox.org/and this might be useful:
http://en.wikipedia.org/wiki/RockboxBest regards,
Vinnie
PS: There are tons of Rockbox topics posted on
www.headfi.com if you do a search there. Those guys are really into it!