There are many versions of the O-OT, most of which can be found on this board. You are correct, it is against the rules to offer bootlegs for sale or inquire about purchasing them. However, you may inquire about trades or request someone willing to PM you about acquiring a set. Most people on this board willing to accomodate you do so for the cost of discs and shipping or less.

Your biggest decision will be which version you would like to own. If you are strictly a PAL person, you have but one choice: Moth3r's set. If, however, you are able to play NTSC DVD's, you have a host of other options. Dr. Gonzo, Cowclops v2, and EditDroid sets are quite poplur at the moment. Have a look at the official project thread as well as the official screenshots thread to compare versions.