I am not clear on how to deploy Apex from developer to a production org.

Specifically, I am looking at the following documentation....

http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_deploying_code.htm

It appears that Apex Classes and triggers must be in a local directory on my machine to use the Ant tool (see understanding CompileAndTest and reference to basedir and the sample directory provided with the Ant download)

Am I supposed to copy them over from developer org to my local hard drive?

I would have thought that somwhere I would provide username/password for my developer org and another username/password for my production org and the system would deploy from developer to production. Seems like I only provide username/password for my production org and the ant tool expects the apex files to be on my local machine...