MSDN Hackable URL's
Here is a neat trick that always comes in handy when looking for a quick reference on classes and their members in .NET. MSDN URL's are hackable; they can simply be called as follows:
http://msdn.microsoft.com/en-us/library/system.net.networkinformation.networkinterface.getisnetworkavailable.aspx
The above returns the page with information about the GetIsNetworkAvailable method in Networkinterface class of System.Net.Networkinformation namespace.
So, for example, you need a reference on ASP. NET Membership class (System.Web.Security). Here is the URL:
http://msdn.microsoft.com/en-us/library/system.web.security.membership.aspx.
So, if you know of a class and/or its members, reference is just a click away.