Congrats. I recently unloaded an Audi for a Toyota and don't regret it.
If you want the most money from it, sell it yourself. Check out some of the car sites (edmunds.com, KBB, autotrader, etc.) for better info on exactly how to do it. I'll bet that each of them has a full article on the topic along with the steps involved and pointers.
If you want the most hassle free experience, sell it to CarMax. From past experience, they seem to offer about the same as what you can get at, if not a teeny bit more, from a dealer, which is typically about 5-10% less than Kelly Blue Book pricing. Dealing with CarMax is much, much better than dealing with a dealer. Either way, don't expect a lot and you won't be disappointed.