I have done quite some xCode programming and found the overview perspective of the methods in a class really helpful. It looks like this:
MY_GROUP_1 <- define
In fact, this is a duplicate of Any way to group methods in Java/Eclipse?.
The Coffee Bytes plugin is mentioned is no longer available at the referred locations. But, it seems that Bartosz Kosarzycki has posted an updated version yesterday:
http://kosiara87.blogspot.com/2011/12/how-to-install-coffee-bytes-plugin-in.html
Note that this does not provide grouping for the outline view, just (customized) folding in the editor.