Aaron (one of the developers on my team working on the SDK) just wrote a couple of great posts for folks wishing to use and to understand how the SDK works for VS 2010 Beta 1. Definitely worth a read if you're working on VS extensions:
- VSIX Project template - The VSIX Project is meant to be a very simple project template that is used for building a raw VSIX “bundle” (i.e. the zip container).
- How PkgDef files (for portable registration) work with the Experimental Instance in the SDK.