At this time, we cannot identify very many  E-temples to Rhea (or real ones in operation, for that matter). The closest we have is this page dedicated to Magna Mater.

There is a Temple of Magna Mater in a Second Life simulation. To go there, click "search" in the menu and type in "magna mater"; you should find it quite easily. This sim also has a Roman villa and other locations. I have nothing to do with this sim, so please direct any questions to its operators. It doesn't seem to have scripting for prayer stances (you know, arms raised towards the heavens while praying to Rhea-Kybele) and may be devoted to a secular cause, but this temple provides a beautiful location and locus for worship if you are comfortable with Internet-based sacred precincts.

If you have a temple, information on an Internet simulation of an ancient temple to Rhea, or sites devoted to her, please contact me at annyihra [at] gmail [dot] com if you want this added to the list.