Hmmm, couldn't find how to do this in Plesk 7, even the online doc / faq didn't tell.

Plesk 7 doesn't have the ability to create reseller accounts??

I know that is a funny thing because they mention doing it in their marketing materials.

WebTec Solutions, Inc. (http://www.webtecinc.com)

Simple.

Create the User as a Client and in the permissions you setup give them domain creation ability.
Under the limits, give them Unlimited domains.

Go to the Plesk site and download the Manuals.