Subcategories - a better way than mine

[eluser]Johan André[/eluser]
Hmmm... Your code is not easy to extend. Let's say you one day want 4 or more levels?
MPTree will do this (i think). Or you can just write an recursive function to output the list.
MPTree will be faster but might be overkill for an adminarea, where you typically have quite few users.
The recursive method will use 1 query per level, compared to MPTTree which only use one to get the whole tree.

Good luck!