We heard something about a product called Onstage at a recent conference. Does anyone have any information about this product?

I've never heard of it. I did a quick search and found this website:

http://www.onstageportal.com/

Many organizations have Microsoft SharePoint for document sharing and team collaboration, and it seems this tool competes with the same type of functionality.

If you have MS Enterprise applications you may already have SharePoint. Check with your IT department.