Microsoft's online MSDN documentation has, for some time, offered a very intuitive way of discovering information about various classes and namespace via direct input into the URL. Effectively you can guess what the location of things you want to look up.
I can for example type the following URL in my browser http://msdn2.microsoft.com/en-us/library/system.io, and get directed to the System.IO namespace documentation. Similarly I can get directly to information on classes by using the same technique. http://msdn2.microsoft.com/en-us/library/system.data.odbc.odbcerror, takes me directly to OdbcError class.