In Andalucía or Extremadura both "seseo" and "ceceo" live together. "Seseo" is /s/ instead of /z/; "ceceo" is /z/ instead of /s/. Seseo is more general than ceceo (although Wikipedia says the contrary). The rest of the country usually pronounces correctly both /s/ (s) and /z/ (c, z).
http://es.wikipedia.org/wiki/Ceceo
http://litart.mforos.com/1084435/683...eo-y-el-seseo/