I use it with 19.99 Media Max bundle. I received an e-mail from Cingular confirmning that I do not need to change my data plan with this phone. I also do not use blackberry services. I use Nokia e-mail application and I am very satisfied with it.
essentially it is vital for blackberry apps but u can get away with the regular unlimited media net service atleast for awhile they will eventually see that u are using a higher data that is not capable on your regular mobile phone and force u to switch to the pda package for the most part if u don't get caught u save the money =)