I've been doing part-time work in Odesk for at least a year (on and off) and so far wala pa man ko ma scam. Before applying for a job make sure to look at the buyer's (employer's) feedback from other contractors. If daghan bati nga feedback, bahala ug taas ang rate and nindut ang job, I don't apply. Kay if dili mo magkasinabot sa buyer, it'll only cause you a headache plus you might get a low feedback score from him. Feedback scores are really important. They up your chances of getting hired faster in the future.