Do you have content rich, English language websites that over 50% of it's visitors are from the US?
My company, SoundSearch, has a unique direct partnership with Yahoo! and offers their Premium Ads, as well as premium ad inventory from other top premium ad agencies, using our proprietary customizable ad units.
Please contact me if you'd like to forward you details and samples. Yahoo Premium Advertising has consitantly proven to outperform Google AdSense. More attractive ad units and higher paying CPCs? Makes sense to give SoundSearch Ad Units a try, don't you think? If you have any questions, by all means contact me at your convenience.