Sharepoint 2007 wildcard searching

To use a wildcard search or part of the name, you must specify the field name you are looking for.

eg. FileName:whiz* will find all documents with a FileName starting with "whiz"

I havent found a way to search on field's with spaces in yet (ie where there is a space in the file name replacing it with _x0020_)

There is a good article here
http://www.novolocus.com/2009/05/27/sharepoint-can-have-wildcard-searching/