First you need to ensure the Vodafone BlackBerry 7100 is unlocked. To do this just insert the SIM and if it can connect to O2 then it is unlocked, if you get a SIM error you will need to obtain an unlock code. Once the device is working with the O2 SIM just call O2 and request they add a "BlackBerry Internet Service (BIS)" data plan to you phone account. Once you have a BIS account click on the link below and create a new account and add your email account\s.