Getting started with Mac programming?

Greetings all,

I am an ASP.NET and VB.NET programmer by trade getting ready to embark on my first Mac program.

I have no idea where to start and I'm looking for some basic advice on things like:

What development environment should I use... what are available?

What programming languages are supported by Snow Leopard and Lion?

The main purpose of this application is very simple:

1) detect when a disc has been inserted into an optical (cd/dvd/bd) drive

2) walk through the folder structure looking for specific patterns

3) copy those folders to a network share

4) eject the disc when finished.

I could bang this out in a day with a PC and Visual Basic, but I thought it would be a good project to get my feet wet.

Any adivce?

Thanks in advance!