help!

[vicx52o]

i recently recieved an iphone as a gift (gift as in just the phone AS IS [no box, cables, dock etc])
my family and i use a family plan and we have unlimited txting for everyone.
ive been looking through a bunch of threads on modmyifone but i cant seem it to get an answer.
the iphone has the 4.6 bootloader and the baseband is 04.03.13_G.
i have a cingular branded 3G sim card.
the iphone is running on a jailbroken 1.1.3 FW.
i really wanna know what i have to do to just use the iphone w/o adding anything to my current voiceplan.

thanks guys

-victor

[Loyalty]

Would it not be just as easy as putting your SIM in (if the phone is activated)??