One Link in PhP program

I have an auction program written in php That requires in the decription a link that can be posted by user. I user ads a link it should turn blue as in aol or other mailing programs. you can see aht i mean if you go to [login to view URL] click on Check out auctions at top of page, then click on 1.14 ct perefect diamond under featured piature gallery,pull down to decription and you will see "see viveo at et-auction.com" that should be a link as of now its not and should be in bold dark blue.