>We are planning to go for C# as our language for .NET
>Is there any available documentation that I can download?

Here's the actual language specification, its surprisingly fairly digestable:
http://msdn.microsoft.com/vstudio/techinfo/articles/upgrade/Csharpdownload.asp

For an actual instruction on how to use C# to create .NET apps (using the base classes, Windows Forms, Web Forms, .NET Remoting, ect.) you should probably find a book. Professional C# from Wrox is a pretty good one, IMO.