Many were confused and wondering weather the PS VITA will use some sort of SIM Card system to use the 3G, however now Sony have cleared things up about the PS VITA 3G.
From the get-go, Sony's Tokyo Game Show press conference was all about the PlayStation Vita. After announcing that the new handheld would arrive in Japan on December 12th, Sony got down to brass tacks as to just what the machine can do.
First up was 3G. In Japan, NTT Docomo will provide the service via a pre-paid plan that supports messaging and gaming services. 20 hours will cost Japanese players 980 Yen, while 100 hours will set them back 4,980 Yen. That's about $10 and $50 respectively, but there was no word on whether or not AT&T – the U.S. 3G provider – would support a similar price structure. The Japanese plans can also be combined with cloud networking, smart phones and tablets.
If Japanese customers aren't ready to make the jump, the Vita will come with a trial version of 3G.
Source:
http://uk.psp.ign.com/articles/119/1194249p1.html