Over the last year I have moved from a beginner PHP developer to a more intermediate developer, I use Mac OS X and a local development server environment (MAMP). 

I am thinking about starting to develop using the .NET framework. Can anyone give me some advice?

* What do I need to begin?
* How similar
is .NET to PHP?
* What is the
relationship between ASP and .NET?
* Is
there anything novel or vital I
should know about developing in .NET? 
(I know .NET is written using
microsoft technologies...)