To get any emails fowarded to your blackberry, you need to buy service. The only possible loophole is most service providers give each cell an email address. It's something like:
. But I believe each time you receive an email it actually comes as an SMS message, so you'll get charged everytime you receive a message. Then you could buy the unlimited SMS package but you're back to paying for receiving emails. Bottom line, you'll have to pay to get emails on your phone.