Be aware of code injection, folks - like anything else you take from the user, SANITISE IT FIRST. This cannot be stressed enough - if I had a dollar for each time I saw code where form input was taken and directly used (by myself as well, I've been stupid too) I'd probably own PHP. While using data from a form in a URL wrapper is asking for trouble, you can greatly minimise the trouble by making sure your inputs are sane and not likely to provide an opening for the LulzSec of the world to cause havoc.
