DVC is a timeshare system. You purchase a real estate interest which is represented by an amount of points. These points can then be used to reserve different accommodations. Different accommodations each require a certain amount of points depending upon the time or year and the size (i.e. studio, 1 bedroom, 2 bedroom, or Grand Villa). There is a FAQ (Frequently Asked Questions) post that you should look at to get more general information.
For information on renting, the Rent/Trade Forum is the best place to get more information. However, its a good idea to understand how DVC works before you decide to rent points. The cost to rent points varies on the person renting them. I've seen everything from $8-$12 depending upon when the points can be used.
Good luck!