Edznaz, funny you should ask this question. I'm doing my military to career transition workshop this week and the instructor (from the Department of Labor) said that you could use Facebook or MySpace to professionally network but that often times personal information that you don't want a prospective employer to findout leaks onto the page.

Other sites to try are:
LinkedIn | Relationships Matter
Ryze business networking

I just learned about them today so can't speak to their aviation or piloting benefits, just putting them out there.