I use global constants to hold function names - then when I need to call a function, I can just pick it from my globals list. Has the added benefit of allowing me to enter in a comment that tells me what the function does, what it returns and/or what parameters it takes.
I usually keep an event sheet called Function Headers, and try to stick to a naming convention like F_FUNCTION_NAME - that way, when looking through globals, I can see all of the functions grouped together. Then I can quickly look at the comment to see how to use it properly.
It's a bit of extra work (and some overhead for the globals as well), but definitely helps to keep things organized. Of course, some sort of built in method of organizing functions would be awesome :)