Is there a ToDo/Tasks service that can sync to windows mobile tasks, so they are accessible offline?
Today I learned I can sync Google calendar to winmo calendar, but not tasks.
Google is notorious for not providing an API for tasks (I encourage you to read the funny comments on this funny thread).
Try RememberTheMilk.com - it provides Outlook integration - and would therefore sync with WinMo.
Toodledo is excellent! I've tried tens of different task management applications and web services, but this is the first one I'm really satisfied with. I use it actively every day, both for private business and at work. I don't know if it syncs with Windows Mobile, however, they do support a number of different export/import and synchronization services - perhaps one of them can work for you.