the PSU is the most important single part of any electronic design. i use a Power One module. the spec is +/-12 volts at 2.5 amps. it runs alll my modular equipment no worries. its also a linear design rather thatn a more modern switched mode supply. a switchmode supply from an old PC might work, but i havent tested it.
ill edit this post a bit later with links to the prower one site and the unit i use. otherwise, there is always Google.
updated 8th march 2011 : It appears that Power One dont make linear power supplies any more. theyve gone all green instead. oh well. find or build a Bipolar 12 volt psu that gives you about 2 amps or more of VERY CLEAN power.
be seeing you