i dont think its BB related, must be the communication to the bb servers, ie Rogers...
I have my 8900 on wifi and i can use bbm, internet, and emails are coming in on my bis accounts.
I have a 9000 on bes, that i havent bothered turning my wifi on as its a work phone and im not working right now
3G, nor EDGE are working... my 8900 on edge and wifi is good to go though.