That depends on the unit. Is it locked / unlocked. You can check your unit first before buying it. If you already have the unit, try to remove your cingular SIM and put it in your Samsung.
HI yes the Samsung F700 mobile will freely work with cingular sim only if it is unlocked one ...Else if the phone is locked to some other network provider then you can't freely use it with any other GSM sim until you unlock it .You can easily get your phone unlocked using sites like WickedUnlock.com they are providing unlock code for all mobile models at reliable cost .....You first check that whether the code is available for your country and network provider .If yes then pay for it and unlock your phone .