The Mac should still be under warranty considering it hasn't been available a whole year yet. If an Apple store is convenient to your location you could make a Genius Bar appointment at Apple.com/retail to have a Genius pop the bottom case off and blow it out for you. Shouldn't take them more than 5-10 minutes.
With that said, if you'd prefer to do it yourself I would refer you to the [guide|18695|teardown of this Mac]. The fan is readily accessible once you've removed the bottom case and as such should be fairly easy to clean. Working through step four of the aforementioned guide should get you to cleaning the fan. Things to keep in mind if you do tackle the cleaning job yourself...
* Be sure to disconnect the battery. Even though you don't have to touch the logic board or other sensitive components it is always a good idea to work on a non-powered unit when it's an option.
* Use quick bursts of compressed air to push debris away from the fan, through the heatsink and out of the Mac.
* To prevent the fan from spinning up (you run the risk of damaging it by over-revving it) I typically apply light pressure with a finger or use a blackstick pressed up against a blade to hold it in place. You can manually spin the fan a bit and repeat the process to clean it out completely.
* Go ahead and use some quick bursts of air on the other areas in the Mac while you have it apart, this will help avoid immediately reintroducing debris to the fan once you seal it back up.
Hopefully that helps!