Portal Guerrero 3 is home to the main Tourism Office (Mon-Fri 9 a.m- 7p-m, Sat-Sun 9 a.m-2 p-m, and Englishspeaking staff person is there after 1 p.m) which has pretty good information. There´s a kiosk on Morelos and 6 Sur beside the pyramid which distributes maps and pamphlets too (an English speaker is there from 10 a.m-3 p.m.).
HSBC on 14 Morelos has an ATM and is open from 9 a.m-7 p.m. Five doors down, Bancomer can change foreign currency (8.30 am- 4 p.m). For contacting home, the post office is on the corner of Avenida Hidalgo and 9 Sur, whilst several internet cafés can be found on 5 Poniente (at 503 and 330 for example) and along studenty 14 Oriente. There´s also several laundries down 14 Oriente (at number 14 and 207 respectively) as well as around town- ask at your hotel for advice on where to go. The hospital is on 7 Sur and 5 Poniente.