Mac Software Business Statistics

I'm thinking to learn about Mac Software development. Does anybody know where I can get some statistics on Mac SW Development business in general? Things I'm looking for are somethings like:
How big of a business it is? (1-billion, 2-billion US dollar business etc.?)
What is the most popular field? (GUI Development, Networking, etc.?)
How does the job market look like out there currently? Shortage of qualified people or already saturated?
etc. etc.

Thanks in advance.

There are many mac software companies out there and many of them are small independents who make a nice living from it. I can't recall seeing any gross numbers though.

I'd have to guess GUI development would be the most popular simply because other items would likely be in some niche. The GUI is easy to code for but may take getting used to if you are coming from something like VB.

Look at job sites such as Dice and Monster. iPhone is the hot ticket right now. Search for the words Cocoa and Objective-C.

This link may give you some inspiration. The same author is on video here discussing Monster Marketing. Also 'Indie Ethos' may be of interest if you are considering that route.