File there or not?

Still a newbie and clums at this stuff and am running into a brick wall with this. I need to pull an item out of the database, turn it to lowercase, and then look to see if the file is located in another directory. If it is then it prints out one thing, if not it prints out another. What I am doing is creating an auto-generation script for pages so that I can input new items to the database and each time the script runs (I'll cron it) the pages will get re-written and so on. My system: PHP 4, MySQL, Apache2 My question: How do I pull the item and turn it to lower? Strtolower? How do I check it against a directory to see if the file exists? Thanks, Robert