How do I find a person by their maiden name free of charge on the web?

Depending on how long she's been married, you might be surprised to find her by Googling her.

Try it three ways - and use the quotes:
"firstname lastname"
"firstname middleinitial lastname"
"lastname firstname"

... if any of the above result in too many hits to search through, try adding a city she lives or lived in (outside of the quotes).

Doing this can result in hits to her referenced on her employers website, in the obituary of a family member, a wedding announcement, a personal site like xanga or myspace, etc.

... it's not a guaranteed method, but certainly worth a shot. I've often found people this way.

www.zabasearch.com