C# can be defined as, "C# is a simple, modern, object oriented, and type-safe programming language derived from C and C++. C# (pronounced C sharp) is firmly planted in the C and C++ family tree of languages, and will immediately be familiar to C and C++ programmers. C# aims to combine the high productivity of Visual Basic and the raw power of C++."

C# is not a upgrade to C++. C# is a totally new Object oriented programming language. You could say its much more easier and Object oriented than C/ C++.

Yes! C# is a RAD (Rapid Application Development) Language like Visual Basic. It supports the Drag- Drop and Build features of Visual Basic.

The C# compiler is not distributed as a separate entity yet. You will need to download the .NET SDK (131 Mb) from http://msdn.microsoft.com/net . The SDK contains the C#, VB.NET, JScript Compilers and full documentation and its Free for download.

First download the .NET SDK. The SDK contains compilers, documentation, code samples and Quick Start pages to help you learn faster. You can also visit many web sites which provide tutorials and articles on .NET.

Check out www.dotnetbook.com they have a listing of all books available for the .NET platform. I have no personal recommendations since I haven't yet read any of the books available. As for the question of free On-line books, there are inline which I know. If you are in India check out www.grenleaf.com. 

If you are a Java programmer then you will find it very easy to migrate to C# (I did migrate from Java to C#). Also if you are a C / C++ programmer then you will find much similar syntax of C#.

The answer to this is a bit tactical. C# applications cannot run without the .NET runtime. At present the .NET platform has been released for Win98/ME and Win NT/2000/XP. Microsoft plans to release the .NET runtime for other platforms soon. Now if, a .NET runtime has been released for your platform then all the .NET programs will run on your platform. This is quite similar to the working of SUN Java which is considered to be Platform Independent. In the case of Sun Java you need to install a Java Virtual Machine on your Platform to run Java programs. If your platform does not have a Java VM then it cannot run Java programs. Hence you can consider the concept Java VM similar to the .NET Runtime Environment (not literally ). You can check out the Mono Project where they are porting the .NET Platform and the C# compiler to the Linux platform - www.go-mono.com.

There is a separate .NET Redistributable runtime (20 MB) available, which can be used to install on the client's machine.

Read this article for more information.

Yes, C# is a fully Object Oriented Programming Language.

Again a very debated topic , I would just say that it should have a good future or else I would not be into C#, right!

The .NET SDK has enough documentation. But if you still need some more info then check out the resources section on my site.

Yes, C# and the CLI specifications were submitted by Microsoft to the ECMA, and they have been ratified as standards.

Java or C / C++ knowledge or either ONE of these languages will do. But be sure to get your OOP (Object Oriented Programming) concepts clear. Although I think Java programmers will find C# easier. But C++ programmers will also feel at comfortable since a lot of C# syntax is similar to C++.

You can use any text editor like notepad, to write your C# codes. Just remember to save your C# source code files with the extension .cs.

If you have installed the .NET SDK then you shall generally find the C# compiler (csc.exe) in the directory
C:\WINNT\Microsoft.NET\Framework\v1.0.xxxx\ (for windows2000/NT)
or
C:\Windows\Microsoft.NET\Framework\v1.0.xxxx (for Win 98/ME)