Edit your default filter to not forward on your BB (you can only edit BES filters this way).
Messages->Options->Email Filters and set "In no filters apply send email to handheld" to No. If you have any other filters that allow email forwarding you need to set them to not forward as well.
Originally Posted by joemz
Will I be charged for voice calls I don't answer, or for voicemails left for me?
As with any roaming outside the US you will actually get billed at twice
the international roaming rate for calls that go to voicemail (once for the call being redirected outside the US and once for the call being redirected back to the US to your voicemail center). Your phone has to be turned off to avoid this.