Hi,

Is it possible to use BES over WiFi on a BIS-only enabled sim? Assuming the BES is located within the WiFi network...

This is because the BES plans on my carrier are too expensive for me, it would be good to at least have access to BES functions while in WiFi range!

I think, it is possible to activate a BB using WiFi (like using USB), but then, all communication will be done using the RIM network - and, unless you have a BES subscription you cant connect to the BES.