Agendus for Windows Mobile Pocket PC Professional

From Iambic:

Agendus makes it easy to schedule meetings, write tasks, create contacts, and check e-mail with confidence. Its contact management capabilities are superb. You can do everything from grouping, sorting, filtering, and searching, to tracking contact history, checking the weather at the contacts location, obtaining driving directions and customizing your contacts profile to include photos, or birthday alerts.

Agendus has advanced features such as Power Search, full color and icon support and Over-the-Air (OTA) capabilities. Plus, it was designed for one-handed navigation, which makes using it, while on-the-go, a snap.