This might be helpful info to newcomers moving to our Valley or to first time buyers moving into a new home who never had to think about utility companies before.
APS, Arizona Public Service, provides electric to much of the Valley. You can contact them at 602.371.7171 or www.APS.com.
SRP, Salt River Project provides electric services to a good deal of the East Valley too. You can contact them at 602.236.8888 or www.SRPnet.com.
Southwest Gas provides (shockingly!) gas services to the metro Phoenix area. They're at 602.861.1999 or www.SWGas.com. The City of Mesa handles gas services to parts of Queen Creek; reach them at 480.644.2221 or www.MesaAS.gov.
Note that if you're buying a bank owned home, the utilities will almost always be off. To properly do a home inspection, the buyer must turn on the utilities in their own name. You're dealing with government and quasi-government entities so expect unhlepful customer service people, long waits, bad Muzak and general disappointment and frustration.
Personally, I can tell you that the City of Mesa's gas service policies and customer service are the worst. APS is just about as good as it gets in utility land and most of the customer service folks who work for Southwest Gas are really friendly, happy people.