Here are the basic elements of what you will need to start a medical staffing agency.

Monster Account with Resume Search
Every staffing company of one starts here.  This is how you will build a database.  For every resume that you view, you should copy their name, expertise, email, phone number, and city into a spreadsheet.

Constant Contact Account
This is where your emails will go.  As you get clients that have needs, you will be able to distribute those jobs to the candidates that you have found online.

Top Notch LinkedIn Account
Your linkedin account needs to rock. That means that you should have a call to action and it should be updated with current information.  Optimize it to come up in linkedin search for the jobs you are trying to fill.  Check your mail three times a day.

Twitter Account
This is another way to distrobute your jobs.  Tie in your twitter account with your linkedin account.  This will allow all of your linkedin connections to get your tweets about new jobs.