Introduction To .NET
Let's start by quoting from wikipedia: "The .NET Framework (pronounced dot net) is a software framework for Microsoft Windows operating systems. It includes a large library, and it supports several programming languages which allows language interoperability (each language can use code written in other languages). The .NET library is available to all the programming languages that .NET supports."
Our definition: .NET Framework is a great developing plateform that allows you to do everything you want the way you want!
Question : I use PHP, why should I change?
The answer is pretty simple: PHP allows you to build websites only, but with the .NET you can build Websites, Windows, Linux, Mac,Windows Phone, iOS, Android Apps, and websites, you can also build SilverLight/WPF Apps! all this with one language! awesome no? You can even query databases with your language!
Next, the .NET Framework languages are managed, that means you don't have to worry about unloading variables or about crashing the system, the GC will do every thing for you! It will unload everything unnecessary from the memory without your intervention! And with the JIT you will compile only what you need when you need, it is not necessary any more to compile your entire code when you are going to use only one method! The JIT will compile your MSIL code to Machine code when and only when you need it to provide you a better performance.
This is not what the .NET Framework offer, no, this is only a small part of it's features, this framework offers a very huge Base Class Library that provide you all what you need, from the user interface to the data access, one important thing about the data access, if you are not familliar with databases and SQL Syntax don't worry! The new Entity Framework allows you to treat Databases' tables as objects! something you are familliar with! And the LINQ (Language INtegrated Query) allows you to query your database within your code with your .NET programming language! Wether your querying a XML File, a SQL Server Database, Oracle Database, MySQL Database.. You will use one unified querying suntax!
After building your first app using this framework, you will be surprised : "Wow! How was that easy!" either you are new to the developement or you are comming from another platform or language (PHP, Java, VB6 …etc).
With the .NET Framework, building apps was never easier!