Hi, yes the MacBook Pro can pick up other wi-fi no problem, in the room it detects about 15 other networks and can log on ok, I am connected to another network currently.
I programed the Express with the MacBook Pro last month so it did pick it up then (not sure if I have had a system update since then).
Strangely enough since I wrote 15 hours ago it has now detected the network I need and has logged on. However the Utility still doesn't detect it until the machine is logged on, it says: 'Unable to find any Airport devices', then when I log on it pops up in the utility ok.
So it seems to be an intermittent problem.............. the worst kind!