One of my favorite development tools is Google.  It's better than MSDN's built in search at putting the links I want at the top.  For example, you can search for "site:microsoft.com Some Class, Method, etc." and quickly get MSDN docs on anything that's bugging you.  And what developer hasn't Googled an error message? 

Now there's a new feature in Google labs that lets you search public source code.  Obviously, you'll need to be wary of licensing issues, but if you want to see how a, say, an HttpHandler is used "in the wild", you'd just search lang:C# (or VB.NET, etc), and the keyword. 

One caveat: there's tons of bad code (tm) out there.  Even on MSDN, there are hard-coded connection strings, unclosed readers, and un-disposed disposables galore.  Don't use Google as a crutch for really learning your trade!