I just got an email from JetBrains with some content about ReSharper 4.0 for Visual Studio 2008, that I am sharing here:

Comprehensive support for C# 3.0 language features**, including:

  • New code analysis, context actions and quick-fixes
  • New refactorings (such as Convert to Extension Method, Convert to Automatic Property, Convert Anonymous Type to Named)
  • Many more intelligence and productivity features
    Full set of refactorings available for VB.NET. Compiled libraries are now taken into account in null-reference analysis thanks to external annotations. Stardard libraries come with pre-packaged annotations.
    Code Cleanup - a tool for ensuring compliance with code guidelines and enhancing code structure. Complete Statement - a feature that will complete language constructs and get you ready to write the next statement.
    ** Many other enhancements and new features throughout the product.