- It should, though your older Express is not capable of many advantageous features of newer AirPort Base Stations.
- You need a version of AirPort Utility earlier than 6.0, depending on the version of OS X you are using.
Lion, Mountain Lion: AirPort Utility 5.6
Snow Leopard: AirPort Utility 5.6.1
Leopard or Snow Leopard: AirPort Utility 5.5.3
Tiger: AirPort Utility 5.4.2
Panther: AirPort 4.2
Jaguar: AirPort 3.1.1
even older versions: http://support.apple.com/kb/HT1998
The option to plug directly into the wall power socket makes it really nice.
It is a clever design feature, but wall sockets are often behind furniture and usually near the floor - both less than ideal locations for a wireless device. Perhaps those considerations contributed to its elimination in the new model.
I hope the OP paid only a few dollars for it; much more than that is not worth it. The 802.11n Express is only about $50 used and much more capable than the original model, but at that price the new dual band Express should be seriously considered.