In Visual Studio .NET 2003, the object browser allows you to browse all assemblies referenced by your current project.  In Whidbey, the object browser provides slightly different functionality, so stay tuned for Whidbey tips and tricks once beta 2 comes out.

Alt+F12 allows you to do a search for a specified symbol in the assemblies listed

Alt+- and Alt+Shift+- allows you to perform forward and backward navigation within the object browser

Happy Editing!