It's at http://modelingcommons.org/, and is for NetLogo models. (Yay, NetLogo!)

It's far from perfect, and I really need to do some maintenance on it one of these days. But as things stand, I have the largest public collection of agent-based models. One of my committee members told me that another research group had done something similar, but with a multi-million dollar NSF grant. That certainly made my day!

Let me know if you have issues/bugs/whatever!