If you mean with advanced find, you can't. You could add all contacts to a marketing list and then remove the ones you HAVE contacted.
Alternatively you could do it with SRS using the report writer or with Excel by modifying the query.
Leon Tribe
Want to hear me talk about all things CRM? Check out my blog
or hear me tweet @leontribe
Want to hear me talk about all things CRM? Check out my blog
http://leontribe.blogspot.com/ or hear me tweet @leontribe