The best place to get Carbon information is from Apple's Developer Site. You can find the documentation for the entire API [here]. If you are new to Carbon, the first document to read is Apple's [Carbon Overview].
The Carbon Headers also contain detailed information on each API, including the OS each API was introduced in.
Some of the docs are in both HTML and pdf formats. Some of it is only available in HTML format.
If you know the method name you can do a search for it and find references to the documentation and sometimes example code. BEWARE THE EXAMPLE CODE! I say this because the search will often dredge up old Classic code that has been deprecated by Carbon. This makes it very confusing when you are trying to get started with Carbon.
There are two main compiler choices for developing Carbon apps:
Is there anything equivalent to codeguru.com or devx.com for Carbon Development in C/C++?