Macbook Pro Keyboard

Hello,
I have a macbook pro core duo and as i was working on wordpress today for someone, It has come to my attention that my right button does not work anymore. I am not exactly sure when this happened as i swore it was working yesterday. Anyways, If i take it to apple would they replace it for free, or does a keyboard button that doesn't work require a full keyboard replacement?
I'm not exactly sure what's wrong with it, i figure i'll let it go see if it fixes itself, since I do not see any reason it should do this. It is just frustrating as this would require (assuming i want a working keyboard) a keyboard replacement. I guess i could get by with an external keyboard but that sounds like a hassle to me haha.

All Apple computers come with one free year of AppleCare protection, so if your computer is less than a year old, they'll be able to fix it. Depending on what the problem is, they might be able to fiddle with it right there in the store and hand it right back to you.