the iPhone can access the mail without any other assistance.
Not sure about the data plan change though.
My employer is going to get me a license to have Good Mobile Messanging on my iPhone 4 so that I can access my work email. Will Good Mobile Messaging work with my $30 unlimited data plan, or will I have to upgrade my data plan to a $45 enterprise data plan? My IT guy seems to think I'll have to upgrade to the enterprise data plan.