Below you'll find a link to the search that Jamie refers to in his answer. The Members tab is already selected so just type away. You can search by name, or keyword, and by location.
Let us know if you have any other questions.
You can type in your friends name in the search box on the home page of Trulia Voices. There is a tab right below the search results called 'Members' that will show the profiles of members matching your search.
Hope this helps,