Can't find air printer: Help?

Without any details all we can do is guess and offer general suggestions. Have you worked through all the troubleshooting steps in the support article from which you came? Confirmed that your printer supports AirPrint? Checked with the printer manufacturer to see if there is any firmware update available/necessary?

Regards.

What model of printer? Is it on the list on this support page?

http://support.apple.com/kb/ht4356