In order to win one of the devices you will have to follow BlackBerry on Twitter and tweet the following message:
"what you are most excited about for BlackBerry 10, and include the hashtag #BlackBerry10TO".You will have to be a resident of Canada (excluding Quebec) or the U.S. in order to be eligible to enter the contest. Winners will be notified through a direct Twitter message between January 23, 2013 and January 28, 2013. If you understand the rules, you can take a chance at winning the device by following the source link for the complete rules and restrictions.
source – BlackBerry