CIDR Lookup?

[eluser]Sean Gates[/eluser]
We used a 3rd party database and API that did the lookup for us. We were restricting our site based on non-US IP addresses because we were selling music (copyright freaks in the US ban you from selling to foreigners).

I have to go back and find out who it was, but we basically used the PHP code that they supplied to us, and it was as easy as setting up a PHP object to grab the user's IP data.

-- Sean