If you're a Blackberry user, you may have noticed the downtime with their services. According to this article on CTV News:

The Ontario-based RIM has been dealing with a failure within the company's own infrastructure, which has been the cause of similar problems for BlackBerry users in other countries this week.

Visit http://isblackberrystillbroken.com/ to find out on when service is back and read on news related to the issue. The site was built independently from RIM.