I recently redesigned one of my niche sites & am looking for advertisers. For the new design, I incorporated a premium 468x60 position in the header and decided to go with HTTPAds to help sell the space & handle the admin for clients.
The site is ToyotaCelicas.com...about as targeted as you can get for an automotive site, unless I only focused on a single generation or maybe just the gt4.
Anyhow, if you are interested, just go to the site and click on "Advertising" in the left nav.

FreeCallz.com - Free and cheap phone services.