Check Jobslinger.com for companies that shop your area. The jobs you see posted are likely to be gone but the companies that posted them are likely to have the same clients next month.
Reading through this section will give you a general idea of what is involved and how it works. Many companies have you "certify" for the jobs you want to take either before you can request them or between the time you are awarded them and peform them. What they specifically need is usually reasonably clearly set forth in the job instructions.