Okay, here's a higher degree of difficulty thought. I've got about 1200 CDs already ripped and 600 to go. I'm going to ship those 600 off first, but after that I've got the remaining CDs, many of which were ripped at low bitrates back when I didn't know any better.

For many of those CDs, I went above and beyond the call of duty in annotating the ID3 tags, including putting in BPMs and whatnot. Everything is stored and managed by iTunes. Let's say I send off these CDs to a ripping service, getting back a giant pile of Apple Lossless tunes. Is there any way I might be able to move my metadata over in a semi-automated fashion?