APPA Mundi Tasks app available for Windows Phone 7, syncs with Exchange tasks.

APPA Mundi Tasks is an advanced Task manager application which synchronizes
with your Exchange Server mailbox to make your task list available on the
move.

• Filter your Task list by Status
• Sort your Tasks by Status, Priority, Subject, Start Date or Due Date
• Create new Tasks on your Windows Phone
• Edit and Delete existing Tasks
• Synchronize with Microsoft Exchange Server 2007 and later
• Trial version supports a maximum of 4 Tasks