If you already have and are using Outlook, just download and install ActiveSync from the Microsoft website:
http://www.microsoft.com/windowsmobi...ivesync37.mspx
ActiveSync will keep your contacts, calendar, e-mail, etc... synchronized on your PDA and desktop. It also let's you directly view/explore the PDA files from you desktop so you can manually drag and drop files both ways. ActiveSync also lets you install apps onto your PDA -- just run the installers while ActiveSync is running and they'll get transferred to your PDA.
The two most popular add-on PIMs (Personal Information Managers) are:
WebIS Pocket Informant 5
http://www.pocketinformant.com/p_pocketinformant.php
Agenda Fusion 6
http://www.developerone.com/agendafusion/
They are both EXCELLENT.