From ClickZ
A sample of Internet Yellow Pages that you might want to double check that your site is listed on or if you should buy a paid listing of sorts:
Verizon SuperPages. SuperPages listings are purchased from Verizon and powered by customized FindWhat.com technology. The tiered results are syndicated to other portals, including MSN, but the PPC listings are not.
Switchboard.com. Switchboard.com (recently acquired by InfoSpace) sells listings directly by category. It’s partnered with Google to show relevant ads to searchers. However, my tests indicate the Google ads shown aren’t locally targeted based on search query but instead are national directories for the category searched.
Yahoo! Yellow Pages. The Yahoo Yellow Pages uses a tiered approach. Monthly fees are based on the tier and category. Yahoo’s yellow pages don’t (yet) use Overture’s local targeting or paid placement results.
YellowPages.com. This service sells listings directly by category and is partnered with ePilot.com (Interchange Corporation) to show relevant ads to searchers.
YP.com. Like Switchboard.com, it sells listings directly by category and is partnered with Google to show relevant ads to searchers. I did see more instances of geotargeted Google results at YP.com.