AT&T Corp said yesterday it will launch local calling services for small and medium-sized business customers beginning in California on February 3, gradually extending to other states. The service is aimed at companies that typically spend up to $2,500 a month on telecommunications services and is possible because of a resale deal with Pacific Telesis Group Inc, and customers in California will pay $10.32 per month per line, and less than two cents a minute for local calls, whatever the time of day, and the service will offer speed dialing, call forwarding, caller ID and other such features. Businesses will be able to keep their existing numbers; business customers in GTE Corp’s California territories will not immediately be able to get the service because AT&T does not yet have an agreement with GTE to resell local circuits.