I know I've seen several people here on CC who used to be active in that thread. I thought about restarting it, but then I found this website that uses the same concept (only with a much larger selection):
You list at least 9 books you're willing to swap, and you get 3 "credits" (which will buy you 3 books or 1.5 audio books). The "seller" always pays the media mail shipping (so if someone wants one of the books that you listed, you pay to mail it, and when you order a book, the owner of the book pays to mail it to you).
I am not here to solicit referrals, which is why I posted the basic link above first. If you feel like being nice and putting me down as your referral, I would get free "credits" (my profile nickname is "trillian") -- But, again, my reason for posting is to promote the site because I think it's a cool idea.
I added a bunch of books last night, and by this morning 8 of them had been requested and I'm waiting to hear about 2 more! I also have 2 books on their way to me (and will obviously start looking for several more).
No, you can just wrap the book like you normally would and write the info on the packaging -- It does help to pull up the label online, though, because it will tell you the amount of postage you need (another very cool feature, so you don't have to go to the post office). You'll also need to make sure you write "Media Mail" on your packaging.