A couple of articles that promote or review online usability services. Some of these I've tried, some I've yet to explore.
If anyone tries any of these out, leave a comment. I'll blog any that I find to be useful.
22 Cheap or Free Web Usability Tools, Part 1 (the first 6)
Turn Right On Usability Lane
Of those listed, I'm currently trying out userfly.com, usertesting.com and fivesecondtest.com...