Can anybody recommend a simple, effective and cheap way to redirect people based on their location (down to Country level)

The scenario is that I have an online store which can sell items to the US and Europe. The trouble is that, in order to service each area properly, I need to separate them out.

When somebody hits the website i wish to use some sort of redirection so that US visitors go to mydomain.com/us/etc and the EU customers go to mydomain.com/eu/etc

Whether this is achieved with a meta tag, java scripting or another method is fine with me.

Thanks in advance.