S4BB has just released TaskMailer which adds an interesting feature to the built in tasks application on your BlackBerry. It lets you import and send out tasks using just simple emails with iCal and vCal attachments. The tasks can be emailed to anyone with two clicks and can be delegated into other peoples calendars with attachments.
The downside of TaskMailer is that the app is currently selling for $9.99 which is way to high. Personally I think $2-$4 is a more reasonable price for such an app. Hopefully S4BB will put the app on sale soon.