Redirect script with variables

I wish to provide my affiliates with short clean url's. If I give them this: [login to view URL] I need a script that will parse the last six digits (the affiliate ID) and redirect to: [login to view URL] inserting the affiliate six digit ID in the redirect url. Here is what I found on another web site: [What you then do is create a script called affiliate, note there is no PHP extension. When you access the script you can type info behind it like /haha and that gets stored into the pathinfo var. So a url like [login to view URL] is actually calling the script called affiliate and passing it the word haha as a info in the pathinfo variable.] Is this the safest way to do this? Could the script handle thousands of calls? Are there any limitations? Your comments and/or a quote would be much appreciated. With thanks. Mike Jones