The out-of-the-box SharePoint 2007 people search lacks a central feature that most people take for granted; the ability to search for persons using partial names. The search engine itself has this capability through the property "starts with" mechanism, as shown in People Search Content Editor Web Part by Larry Kuhn.
I've improved a bit on Larry's wildcard people search web-part, by adding prefilling of the search boxes with the searched for values from the query string. I've also added maxlength 32 on the text boxes to avoid overruns. Note that this new functionality is not fully working when in page edit mode due to some extra encoding of the query string in edit mode.
Download the improved wildcard people search web-part here: PeopleSearchWildcard.dwp