Obviously, you need to be on Subscription to download. Here are the links:
eTransmit for Autodesk Revit 2012 Extension 2012-05-31
eTransmit for Autodesk Revit 2013 Extension 2012-05-10
One interesting error that I came across was:
A file with the same name but a different path has already been transmitted.
Here are items eTransmit currently includes:
PS - I remember how excited I was when I first saw eTransmit for AutoCAD! I'm not that old, am I?