daw - firstly remember GPRS costs NOUGHT unless you download bytes. If you 'filter' your emails and check 'headers' so you do not download HUGE attachments you should find it pretty cheap. Basic emails are pretty low on bytes, and time on line is not charged. Web browsing will be more expensive and best done either via wifi or at the library/Internet cafe.
1) Any of the connection methods should work - I use Bluetooth. The service provider (make sure they offer GPRS facilities on your particular tariff) will have a 'set-up' help prog. Orange do. Check their website.
2) No