...Visit the parks and ask around. Because the nannies always are either looking or know someone who's looking for placement. Chatting up parents and etc. Then check references.

...I never did it, but you may want to place an ad in a local college newspaper. I know of people who have hired part-time nannies this way.

We tried the idea of visiting the parks, which we like to do anyway during nice weather. We got to know some nannies and selected one. As nice as she seemed, I still wanted to do a pre-employment background check on her. Then I found out that I have to obey the Fair Credit Reporting Act (FCRA) because I am now an employer. Individuals can just do a background check on anyone, but employers must follow the FCRA guidelines, which mainly say two things:
a) The employer must get written permission from the job applicant before the employer buys a background check on the job applicant. I just put the permission form in with the job application and they always sign it for me.
b) If you do not hire her because of something in the background check, you must tell her what the information was and where you got it. Ok, no problem. I just give her a copy of the paragraph that describes the problem, and I tell her the name of the company that sold me the background check.

The pre-employment background check cost me under $30 and it covered a lot of stuff. Pre Employment Screen Background Checks include Verification of identity, SSN, employment history, education, and address history. Checks State and county criminal records, sexual offender, terrorist watch, credit check, bankruptcy. Federal criminal records available. Records were matched by name & birthday. Maybe it seemed even a little invasive, but I am glad that we had the background check done. I would not want to put my children at risk with someone that had a criminal record, which I did not know about, or maybe they were just falsifying their previous employment to fool me for some reason.