Systems That Neu Supports
At the moment Neu only works on system 10.6 and higher.
The main reason for this is that the Finder in OS X 10.6 uses a completely different mechanism for adding menu commands than the previous versions did.
Thus supporting both the old 10.5 finder and the new 10.6 one involves a bit of work.
That said, it's not impossible to do, so one day I may port Neu back to earlier systems. Please yell if you would be keen to see this happen!