Moved to Video Games, for obvious reasons.
As for the problem itself, what model DS is it (Phat, Lite, i, i XL)? Also, what country are you in (need to know which branch of Nintendo to go with)? Other than blowing on the buttons like you already have, I don't have any solutions.
And if you do the standard mailing procedure, it's going to run you $85 USD, last I checked (unless you have a warranty on it). That should get you a replacement DS in a few days, just in time for BW (it doesn't come with a stylus or GBA slot protector, and I'm not sure if you have to mail in your current DS). Alternatively, there is a $75 USD route, and that'll get you a simple repair (obviously, you'd have to mail it in, and it takes a few weeks). Both come with 30 or 90 day warranties.
(I'll update this later when I get specifics, this was just off the top of my head)
Edit: It seems they may of gotten rid of the $85 option. Well, at least I was wrong about the $75 option taking a few weeks; it seems it's supposed to take 10 business days after Nintendo receives it.
Also, you may want to post this on
Nintendo's tech support forums. They'll probably end up telling you to schedule a repair with Nintendo, but it's worth a shot.
And for any and all of these questions, you may just want to call Nintendo's support line at 1-800-255-3700.