I have heard the phrase "Google him or her"-----how do you do that,
what information about the person do you need to know (can you just
know their first and last name???)

"Jane Doe" (with the quotes) is a good place to start. Try the persons
proper name as well as nickname. Also try user names and email
addresses.

Then, you can try sites like these:

US Search
http://www.ussearch.com/consumer/index.jsp

Search Systems Free Public Records Directory
http://www.searchsystems.net/

Many states, counties and cities have searchable databases as well.
You can search property records and court cases.

Here's an example with Clark County, Nevada  (Las Vegas)
MAIN:  http://courtgate.coca.co.clark.nv.us:8490/
COURT CASES:  http://courtgate.coca.co.clark.nv.us/DistrictCourt/asp/SearchPartyOptions.asp
PROPERTY:  http://www.co.clark.nv.us/clerk/Records.htm 

Hope this helps.

~~Cynthia