I don't think you can based on the following from Fido's website:
Will Fido's customers now have access to Rogers Wireless handsets and devices such as the Treo or the Blackberry? |
• No. Although Fido and Rogers Wireless are now owned by the same company, they are separate brands and each offers its own selection of unique handsets and monthly packages.
• Fido customers will have access only to the products and services offered by Fido.
To me, this sounds like as a Fido customer you cannot get a blackberry plan, as they do not appear to offer one on your website. You would have to move over to Rogers when/if your Fido contract is up.