To tell Active Sync what you want and don't want it to sync:

1.) Open Active Sync on your computer
2.) Connect your handheld
3.) In Active Sync on your computer, pull down Tools'Options
4.) You'll see a list of the things Active Sync can manage, including Contacts, Calendar, Email, Tasks, Notes, etc.
5.) Check only those you wish to sync.
6.) Some options, such as calendar, have additional options you reach by pressing "settings." You can tell it how far back to download your calendar, for example.

Limiting the amount of outdated information on your handheld will help conserve space on the device. And it makes sifting through to find what you want less taxing.