PhpDig.net - Suggest URL

When people visit the site, is it possible to set up a "ADD URL" or "SUGGEST URL" page.
That way visitors can suggest a web site to list.

I visited one of the web sites listed in the forum and they have it set up so that visitors can suggest a URL next to the search box.

I was just wondering how it could be done ot is it already built in and I just can't find out how to do it.

By reading the forum I have managed to get all the web sites that have been spidered to be included in the results, it would be nice to allow people to suggest web sites.
I am trying to set up a community based search engine and it would be cool if visitors could suggest a site.

I will await any replies, the more I play with this software the more I reaslise just how good it really is.

Many thanks everyone.
Dave Andrews