Can any standard 5v DC adaptor and USB cable be used for the
beagleboard? Are these cables different for the xM and C4 revisions?
Bests,
--Nastaran
There is nothing as standard - you need to match the plug and voltage.
The output current is also required enough to pump the board. 
K410
You can refer to the System Reference Manual which describes what is required. The cables are the same for the BeagleBoard and the BeagleBoard-xM.
http://beagleboard.org/hardware/design
Gerald