Which one has better outlook for learning: ASP.NET 2.0 or PHP?

I know that PHP is free and it use by small company. However, for me that have plan to go to big cooperation, I think it is better to learn ASP.NET. Now, I am thinking to learn ASP.NET 2.0 to create a website. However, I notice that I need to use C# or VB with ASP.NET 2.0 to create a website. I would like to know which programming language is easier to use (C# or VB) for someone like me who knows Java and C? Even though the ASP.NET 2.0 is free, I think I need a complier for C# or VB. Is there any place that I can find a free complier for C# or VB?