I really don't have anything to say about the Googlebot that isn't said anywhere else; here's the wikipedia link. Presumably anyone reading this can use google to get more information; if for some reason you feel that neither wikipedia or google are good sources for this topic here are a bunch of other search engines:
At fault for this one: Jim again, who had never heard the word "googlebot" until Sunday. LUS3R!
(Introduction to this series here)
 Googlebot, although one process, is a multiplicity of processes. Apparently.