Being astute music listeners, you out there in vF-land may have already heard of lala. But if not, you may find it interesting. It is a service through which you trade your old cd's for others' old cd's. You don't trade directly; you trade into and out of a pool. You pay $1.49 for each disc received, which covers prepaid mailers and protective cases. Plus the artists get $.20 for each disc traded.
It is in beta, but is easy to get into. I have been a member for a week or so and have already passed along several discs I didn't listen to. This could be good for people with lots of discs, who probably also have a number of discs they don't listen to. You can get invites by going through PC World: blogs.pcworld.com/staffblog/archives/001571.html
This not perfect by any stretch. For starters, finding and passing on very obscure music is not very likely at this point. However, they have set it up in such a way that there is no harm in giving it a try.