We have to do some Sharepoint development on a 64-bit machine using Visual Studio 2005. However from initial searches, it looks like 64-bit support was added in a version (1.3 that only supports Visual Studio 2008.
When trying to install the 32-bit 1.1 version (the one that works with Visual Studio 2005), it gives an error saying the package won't work with 64-bit machines.