Looking for a couple of hacks.....

I am looking for a couple of hacks to add to my vBulletin forum.

1. People buy and sell things on my forum, and I would like a nice and easy way for them to leave feedback about each other using their forum username and also their email address.

2. I would also like a way to have people rate various products and also leave feedback about them. I have seen this done very well on a site using vBulletin, and was just wondering how it was done.

I just spend about an hour looking through old posts, and I couldnt find anything.

Please help!!!

Thanks,

-JRW