There is no task application on Windows Phone 7 and so there’s no way to sync tasks from Outlook 2010 (or earlier versions of Outlook) to WP7. Windows Live (which is now known as Outlook.com) includes a task option that is buried within the Calendar hub, which is still quite limited.
I recently published an article that documents one method you could use to handle your tasks on a windows phone, which you can read here. At the time I also mentioned another method that I was formulating. This method uses a windows live account to manage tasks. It’s a little complicated to set up, but it’s free and integrates nicely with Outlook and the phone’s calendar.