Dial-up is dial-up and be used everywhere where you can phone that number.
Broadband is location-dependent. So for 2 locations you pay for 2 subscriptions. Having the same ISP on both locations doesn't make any difference, financially speaking.
It's not sure even you can use the same email-address for a pop3-account on different locations (webbased, like gmail or yahoo would be fine, of course), even with one and the same ISP.
I am using MSN Dialup which works both in Arizona and in Illinois. I want to switch to broadband but I need it to work in both Arizona and in Illinois. Does anyone have information on this?