Advertising with sites and magazines that are visited and read by webmasters is also a great way...Check sig
Currently, people are doing offering "bonus" weeks / days / etc. to webmasters...Send 5 joins to
www.xxx.com and get $50 PPS. Problem with that is the cost to the program...
As previously mentioned, start getting invovled in the webmaster community, make friends, and look for ways that your sites can help them out...