Alltel specific question about internet sharing

[Matchstick]

I've done a bit of searching around about this. I've never used the Internet Sharing program on my Alltel Titan. But since we just disconnected our broadband service I was thinking about this more and more.

Now my Alltel guy told me when I bought this phone, that using it as a modem (i.e. internet sharing, i think) would cost me extra on my bill. Is this true? I question it since the Internet Sharing program is provided with WM6.1.

Just thought I'd ask you guys before I try it when I get home. I would hate to have an extra charge on a bill that I can already barely pull off. Does using my phone for teh intarwebs on my laptop cost me extra? (i have an unlimited data plan, but the guy said that using the phone for internets on my laptop would be extra)

So the question goes out to all of you on the Alltel network. Any help would be appreciated.