I finally figured it out. I was able to find the NSData+Additions.h class. It was deeply buried within the Colloquy source code. It's a pretty handy class....allows for base 64 encoding of your authentication string with two lines:
Code:
NSString *authString = [[[NSString stringWithFormat:@"%@:%@", username, password] dataUsingEncoding:NSUTF8StringEncoding] base64Encoding];
authString = [NSString stringWithFormat: @"Basic %@", authString];
Thanks to everyone for the help! If you're curious about the open source Colloquy project, you can check it out here:
Development Guide ? Colloquy