I would also discourage you from doing this unless you already have an ongoing source of reliable people who would like to rent from you. Renting to strangers can be risky and frustrating.
You will have lots of competition from others who are already well known and have established businesses with websites. As already mentioned, Disney is not very supportive of renting and prohibits "commercial" renting. At this time, making more than 20 reservations per year will trigger some type of "audit" to see if the owner is renting commercially.
Know that the owner is responsible for the actions of his/her guests and renters - there have been reports here of an owner's account being frozen due to an unpaid bill at check out. (Apparently, the charges came through after check out and rather than try to contact the guest, Disney just decided to freeze the owner's account. Fortunately, the "renter" was a relative of the owner and paid the charges when the owner notified him about them. Even more interesting, the owner didn't even know there was a problem until he tried to use his account to make another reservation.
DVC did not pro-actively notify about either the problem or the freeze). Similarly, if your guest or renter damages the room, you, the owner would be responsible.
Many owners do rent occasionally, when they cannot use the points themselves. Many are successful. However, because of the large numbers who do this, rental prices rise slowly, if at all. Getting $12-$15 per point is tough when others are offering points for $10 or less. Points were renting for $10 in the late 90's and many transactions are still going through at that price.
Think carefully before you proceed. It's not as easy as one might think.