There is no such thing as an HTML script. The HTML is the part that you do yourself.
As I have recommended before on quite a few occasions, Hot Scripts is usually the best place to go for off-the-shelf PHP programs. click here. If you can't find what you need out of nearly 14,000 scripts, then it will likely be hard to find. Remember to cross-check whatever you choose via Secunia in case it has had any vulnerabilities flagged up. As always, do not use a flawed PHP program in any part of your site under any circumstances, unless you want run the risk of a hack at some point in the future. Also click here.