Microsoft has released version 1.1 of the Visual Studio Extensions for Windows SharePoint Services 3.0! These are the tools that you use to build web parts, site definitions, etc. It can be downloaded from
Here. This is a must install for all those developers working on building custom application on and over wss 3.0
Read the complete post at http://dotnetpathak.blogspot.com/2008/02/visual-studio-extensions-for-wss-30.html