I've applied to one before, basically what they did was test me in computer skills (MS Office, typing speed, etc), look over your resume, and then place you in on of their client's office. You work under the supervision of both the client and the temp agency, but it is the temp agency that pays you and whom you have to report to every week, without fail, your hours and schedule.

They say these temp jobs sometimes lead to the client hiring your directly if they like you well enough and you approve. Usually, I think each assignment lasts about 3 months or so.

I never actually got hired because the time I applied, they actually verified my documents and they said there was a problem and to call the verification office to fix it. Since I couldn't do that, I just desisted from that job and just found another one later on. Of course, now, that shouldn't be a problem