1) Welcome to the wonderful world of BookCrossing!
2) Actually, I don't think any BC staff hang out on Tribe. Have you joined any of the BC forums yet? There is one specifically for newbie questions as well as one for more advanced topics, and the Chit-Chat and Book Talk forums alone will suck all of your time away from you. :-)
3) What do you mean by "has no cover"? Do you mean the book is kind of battered and has lost its cover through "natural causes," or is this a "stripped" book that has been reported as destroyed? In either case, it is really up to you whether or not to register the book and/or try to find some way to pass it to a new reader. But keep in mind that damaged books rarely survive in the wild, and stripped books come with a host of ethical dilemmas. For more information, I'd suggest going to the BC site and doing a forum search on "stripped books." N8an's comments are particularly enlightening.

Go to the BC site and read the thread over the past few days (july 26/27) regarding books with no cover. If you found the book that way, it may have been a book that was suppossed to have been destroyed by the book store. Too much detail to post here, go read the post in "Announcements"

I think that for wild releases, you pay not want to release your best books. I have released some brand new books, which have never been journaled. I can only hope they found their way into good hands. Most of the books I have sent to other members as controlled releases and the trades I have received back have really been in very good condition.

If the choice it release or trash, why not release - then it's up to someone else if they pick it up.

As for the store discards missing covers - it's not like we're reselling we're passing along for free so I don't see a problem with that either. They were stripped so others wouldn't sell them.