Start with
NSUInteger prime = 31;
NSUInteger result = 1;
Then for every primitive you do
result = prime * result + var
For objects you use 0 for nil and otherwise their hashcode.
result = prime * result + [var hash];
For booleans you use two different values
result = prime * result + ((var)?1231:1237);
Explanation and Attribution
This is not tcurdt's work, and comments were asking for more explanation, so I believe an edit for attribution is fair.
This algorithm was popularized in the book "Effective Java", and the relevant chapter can currently be found online here. That book popularized the algorithm, which is now a default in a number of Java applications (including Eclipse). It derived, however, from an even older implementation which is variously attributed to Dan Bernstein or Chris Torek. That older algorithm originally floated around on Usenet, and certain attribution is difficult. For example, there is some interesting commentary in this Apache code (search for their names) that references the original source.
Bottom line is, this is a very old, simple hashing algorithm. It is not the most performant, and it is not even proven mathematically to be a "good" algorithm. But it is simple, and a lot of people have used it for a long time with good results, so it has a lot of historical support.
Although Objective-C does indeed appear to be "insane" initially, I encourage you to stick with it. Once you have an "a-ha" moment, suddenly it all starts to make sense. For me it took about 2 weeks of focused Objective-C concentration to really understand the Cocoa frameworks, the language, and how it all fits together. But once I really "got" it, it was very very exciting.
It sounds cliché, but it's true. Stick it out.
Of course, if you're bringing in C++ libraries or existing C++ code, you can use those modules with Objective-C/Objective-C++.
Best Solution
Noticed this in the Facebook Connect source code. Looks pretty solid, give it a shot.