| | Re: if i turn my blackberry 9900 wifi on........
Data will usually go via WiFi rather than the carrier's cell data network. I cannot say "always" nor can I sat for certain. It depends on the WiFi connection and the apps you are using.
Keep in mind that many carriers require you to have a Blackberry data plan active on your account before allowing you to use WiFi.
And please update your profile to reflect your cell carrier. I know that it isn't "blackberry 9900".