How to identify where I am publishing to for use in the pre-build event

Question

I would like to use Nant to create an environment-specific web.config during the build process when I'm publishing to a given location.

For example, when I am publishing to my TEST server, I want the web.config's connection string to point to the TEST database. When in PROD, to the PROD database.

I have Nant working in the pre-build, but only statically.

Is there a way, while Publishing, to identify which Publish Profile I am using, and use that in the Build pre-build event for use by Nant?

Thank you