Revit MEP 2008 included IES VE toolkits when it was released in the spring of 2007. Many, many architects were very upset that only the MEP version was able to interact with the VE toolkits for sustainable design.
Well the architects have been heard. IES has included a Revit Architecture plugin with their newest release. Architects can now analyze their models for sustainability from inside Revit Architecture 2008. Here is the IES press release.
So what are IES VE toolkits?
"The Toolkits are designed to allow architects to undertake top-level building simulation analysis, facilitating sustainable design at the click of a few buttons."
And now a direct link to the toolkit webpage, IES VE Toolkits for Revit Architecture.