Sharp Hiptop 3 / Sidekick 3

Im not sure if this has been posted or not but I got a sk3 yesterday in the mail and i already own a MDA, now with the mda i have the unlimited internet plan and i know that wont work with the sKiii but i was wondering if the skiii plan will work with the mda being that i would just need to have unlimited internet.....

thanks in advance....