general GPRS question
 

I'm having a hard time understanding why the GPRS vendors are making a distinction between email, internet, and WAP services. I've even looked through some configuration instructions and notice IP and authentication differences based on the service. Furthermore, it's not even clear what each service actually entails.

Can someone give me an overview of these differences? Maybe I can deduce the reason for configuration and billing differences if I understood the distinction in service.

My primary GPRS interest is using an email client for IMAP (although contacts/calendar synchronization via ActiveSync would be desirable too). What key terms and phrases should I look out for in order to get the service I need as I research the prepaid and postpaid options by country?

Thanks in advance.

There are no differences in the GPRS-protocol for the different IP-based services. Years ago when WAP 1.1 was in place there was a WAP-Gateway, that had to be configured, but today WAP 2.0 uses direct http-connections, so practically there's no difference whether the GPRS-connection transports a WAP-page, a desktop website, eMail or any other type of data.
However some operators run APNs (access points) that block some or almost all ports, so e.g. they can sell full web access for a higher price than just mobile browsing (which would be limited to port 80 and 8080). But this happens on IP-basis, so a higher protocol layer than GPRS.
Regarding the GPRS-connection, there's no distinction what IP-service is being transmitted.