All for .NET
http://www.microsoft.com/net/
MS downloads (all available downloads)
http://www.microsoft.com/downloads
.NET Framework download
http://www.microsoft.com/downloads/details.aspx?FamilyID=333325fd-ae52-4e35-b531-508d977d32a6&DisplayLang=en
"Express editions" of VS for C#, VB.NET, etc
http://www.microsoft.com/express/default.aspx
http://www.microsoft.com/express/product/