uPnP on home/school router

Just tested a newly purchased Dlink DIR-601 router for our son to take back
to school...
Left it setup with the local 192.168..0.1 address
and plugged it into our local 192.168.1.x network to get a WAN side DHCP
Worked fine - hardwire and WiFi -

I also think I stumbled onto what I thought was an ICS or issue
that I posted in another thread,
but now think it really is the uPnP router feature/setup.
I have that feature disabled on my local routers,
so never really saw it pop up on Windows Network Connections (XP).

So - I read about what uPnP does,
and wondering if and when it really should be enabled ?

"If everything seems to be going well,
you have obviously overlooked something." - Steven Wright