sharepoint documents

Weve had a sharepoint 3.0 install on a “testzone” for a few months now.
One thing that i cant work out is how to store data onto another drive.

The C drive of the server is very small therefore it is getting full when users are adding documents.
Is there anyway of storing this data to another drive on the same server? We have an E drive that has plenty of space.

Someone else must have experienced this problem

Thanks