venture into the world of designing our own plugins. I have no experience with software programming, and I just wanted to know what exactly we're getting ourselves into..?
Congrats! Well, I believe a good start would be to read:
http://developer.apple.com/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/He has a G5 and I have a MacPro, so we'll be programming Universal Binary apps. That being said, I did a search for programming UB, but couldn't find any literature on it.
This may be of help: http://developer.apple.com/documentation/MacOSX/Conceptual/universal_binary/
I've read in other forums about Rosetta and Cocoa; what are those two? Are they languages or environments exclusively for the non-Intel G5's?
Rosetta is a translation process that runs a PowerPC binary on an Intel-based Mac: http://developer.apple.com/documentation/MacOSX/Conceptual/universal_binary/universal_binary_exec_a/chapter_7_section_1.html#//apple_ref/doc/uid/TP40002217-CH210-TPXREF101
Cocoa is a broad application environment: http://developer.apple.com/documentation/Cocoa/Conceptual/CocoaFundamentals/Introduction/chapter_1_section_1.html
Also, what things do I need to start? I've downloaded the Core Audio SDK 1.4.3, XCode 2.4.1,
Start by reading the programming guide, then try the tutorial and some sample projects. Understanding how the sample projects work will be key.