1. Freelancer - Pays peanuts and has so many conmen
2. Elance - Pays well but hard to get a job
3. iWriter - Best site for a for writers
4. GlobeSkill.com - This is a new site that's coming up. Seems like it will be a great place to hire some freelancers if you are doing internet marketing.
5. vWorker - Not done much there but seems promising also.
Feel free to add to the list