Here are some useful material references for the beginning Macintosh software developer:

There is a well written and current article at http://maczealots.com/articles/development/ entitledBeginning Mac Development, by Justin Williams, that serves as a good launching off point from Windows software development to Mac software development. Here's an excerpt from the article's introduction:

"This article is meant to be a general overview of the Mac development environment. I want to explain what some of your options are, how to get started, and where to look for help. I won't be explaining Objective-C syntax, reference counting or any other type of specific programming topics. There are plenty of other great resources out there for that can do a far better job at that. I'll link to those later in the article."

I recommend reading Justin's article and following up on his resource links. I also recommend your Mac OS X development library should contain, at a minimum, the following materials:

• Book: Cocoa Programming For Mac OS X, second edition by Aaron Hillegas -- I reference this book in a number of places in this document. Aaron runs The "Big Nerd Ranch" where he teaches Cocoa and Mac OS X development. Web site is www.bignerdranch.com.
• Book: Cocoa Programming by Scott Anguish, Erik M. Buck, and Donald A. Yacktman -- I operate from the philosophy of "One should always have two books on any given subject in order to get the broader picture." This book is one of my favorite Cocoa "second books" (I have multiple "second books" on Cocoa in my library.)
• Book: Objective-C Pocket Reference by Andrew M. Duncan -- a very handy reference, packed with info. I'm still learning esoteric and useful things from this slim volume.
• Book: Core Mac OS X and Unix Programming by Mark Dalyrymple and Aaron Hillegass -- geek central for getting down and dirty inside of Mac OS X.
• Book: Advanced UNIX Programming, second edition by Marc J. Rochkind -- a recent addition to my library. Very good coverage of named pipes, shared memory, file I/O, etc., etc.

http://developer.apple.com is Apple's main development page. You'll find source code examples and documentation here.

http://lists.apple.com is where Apple maintains numerous developer's mailing lists. Here's where you find them.

http://www.cocoabuilder.com is an invaluable resource for all things Cocoa. Its an aggragate archive for both Apple's cocoa-dev mailing list and macosx-dev mailing lists. This is the first website I visit when I have a Cocoa-related question.

It is quite handy use a two-button mouse with Mac OS X. Though Apple, at this writing, ships only one-button mice with their computers, Mac OS X is very much "two-button savvy". Right-click context menus work in the same fashion as you've come to expect from Windows. If you don't have a two-button mouse, a right mouse click can be simulated by "control-clicking" (holding down the control key while clicking the mouse button.)