Anyone can rent points. Here's how it works. Someone else owns points in the Disney Vacation Club. You rent the use of their points for a stay and they make the reservation in your name. They retain control of the reservation. You can stay at any of the
DVC's (Beach Club, Boardwalk, Saratoga Springs, Old Key West, Villas at Wilderness Lodge) as long as there is availability.
The rooms at the DVCs are on a points system. You can look at the DVC
points charts at the top of this page and it will tell you how many points each night costs. It varies depending on the day of the week (S-R are much cheaper than F&S), the time of year, the DVC, and the size of the room chosen. You add those up for a total number of points and that tells you what you're looking to rent. For example, when we rented, we wanted a one bedroom villa standard view at the BW. We looked that up and it was 16 points a night (in January), we stayed S-W for 4 nights, for a total of 64 points. Then we went looking for someone who was renting 64 points. If you're renting more than 7 months out you need to find someone who owns that particular resort. Within 7 months of your date any points will work at any resort.
On average the points seem to rent for $10 ish, but sometimes you will see them as high as $12 or even $15 for really hard to get stuff, or as little as $6 or $8 if someone has points that must be used immediately before they expire. I would plan on about $10/point. We happened to get $9, so $9 x 64 points = $576 for a 4 night stay in a one bedroom at the Boardwalk. You can see why people think it's a great deal. You find people to rent from on the rent/trade board.
After you find someone, they check availability for you, and if they can get your dates, they make a reservation in your name. Many people will have you sign some kind of contract and you will usually be asked for at least some of the money up front. Everyone does it differently. Work with someone you're comfortable with because it requires trust on both sides, you because you give them money but they control the reservation, and them because they're committing their points, and if you renege it's bad for them. You will usually have to pay the balance 30 days out and then it's yours no matter what, because the member points would be adversely affected if you cancelled at that point, but again, everyone does it differently.
When you get to the DVC, the reservation is in your name, they treat you (usually) like a member, and you get most of the DVC perks. It's all OK with Disney too, so you're not doing anything underhanded.
So that's all I can think of, hope it helps. You can pm me if you have more questions, or ask the people here - they seem to know everything!