I just got back after renting points - it is a great way to save money on very nice accomodations. There is a risk however.
I found the person to rent from on the rent /trade board. I choose someone to work with that had LOTS of posts here on the DIS (not just one or two or 32 ). I wanted someone with a history of being around for a long while. THen I checked out their past posts to get a feel for what this person was like. After that, I contacted them for their terms in renting points.
In my case, we agreed on $10.00 a point (fair value - some charge a little more. Some will charge a little less if they are in a jam and it is close to time when they either have to use points or lose them).
I gave the rented a few dates to be flexable. THey checked for availablity and made the reservation. I sent a BANK check via certified/return receipt mail for the full amount. They sent me a hand written receipt and the paper reservation from Disney which was in my name but sent to their address (has to be this way). In retrospect, next time I'll ask for a signed agreement PRIOR to sending the bank check - signed by both of us - this could be faxed back and forth.
I checked with member services after the reservation was made (they will only tell you if the reservation exisits if you provide all the info - they will not give any more info to non members) I checked it again prior to our trip.
I've never heard of anyone getting "stiffed" on the DIS after renting points from a member. Visit the boards and get a feel for who has been around a long time.