There are many services like eLance.com and Guru.com that are legit. The problem is that they are total cheapskates. I regularly see people offering authors $2 and $5 for 600 word articles. The hourly rate there is a little poor even for those at the bottom of the currency well.
The survey and secret shopper networks are legit also but pay poorly - they are hobby money only.
My recommendation is to avoid that whole scene and use the internet. Affiliate sales are possibly the simplest area to make good money on the internet - BUT you need a mentor. It is nearly impossible to succeed without one.
The courses and names on the internet are a mixed bag. I do have some contacts for people who are genuine BUT I am not annoying my mentors by passing along heaps of tyre kickers.
This is likely to be the topic of a new hub in a few days. Thanks Shil1978 - you have made me think