This is what Apple looks for in software engineers: Smart, gets things done. (I think Joel Splotskey said it first.)

99% of the software written at Apple is in C or some variant thereof. If your C code isn't up to snuff (EDIT: fixed lousy contraction. English skills aren't as important!), you might be able to get a job working in the build farms, but even those people are good coders doing shit work until they can move up.

All that being said, we have a really hard time finding people that can code their way out of a paper bag in C - so much so that we'll even take people without direct Mac OS X experience if they're talented coders. (I'd still prefer to see true macheads, though.)