i had a dead old 45w power adapter, used the extension cable with airport express and it works, baby, it works!!

No way I could have made any space to plug the thing in as is.
Havent tried it with the newer three prong one, but I assume it works too.
On a sidenote, it was a REAL ****ing PITA to set up WDS with my current network. I dunno, it might just be me, but every time I tried to use airport admin utility to fiddle with the WDS settings on the express, the express base station would just `disappear` and whenever i fiddled with the extreme's WDS settings, it would tell me it couldnt change settings on the express, and it really hated my guts until i just reset the express and tried it over with the setup assistant. now it works. i love it. omg its so portable
i scared the crap out of my parents yesterday with airtunes

blasted jay-z and some dmx from the speakers, but that gave me a headache so then i put on some nine inch nails until my parents yelled at me.