I think it's covered by warranty but only 36k miles, so if you're out of warranty the dealer will try to rape you as usual. There are a bunch of threads on this, and the prices that people have been quoted vary wildly from like $25 to $100.

If you can get the part and you don't mind doing it yourself, it's the best way to go. It's a hassle to get to it, but it's not so bad when you think about the dealership trying to charge you $$$ for labor...

As far as how often, I guess it depends on the air quality around your parts. I know I waited a year to change mine and it was pretty dirty -- not NASTY, but bad enough that I'll check every 6 months from now on. If it's still dirty at that interval then I'll move to 3 months, etc.

 

The recommended change interval is around 20K miles, your environment also plays a lot into it. Order the filter online ($25), I swapped mine out and rambergs in less than 5 minutes.

Their are 2 plastic pins underneath the glove box, slid them out and lower the glove box in an angle so the glove box comes out of it's guide slots. Us a flat tip screwdriver to open the filter cover (behind glove box). Once open, slide old out, new in. Reverse everything to put back. Dude, freakin easy...

 

Although Chernmax just stated how to change the filter, you can also consult the owner's manual. As for me, I just took the filter out, washed it with a soft toothbrush, warm water, and dishwashing soap. Let it sit out over night and then put it back in the morning. It worked fine for me. I don't think you could do this for the life of the filter, but certainly once or twice before buying a new one.

 

please read your manual and maintenace book (or old posts) about the air filter....

read the oil forum about oil and filters.