I've been using Google Sync for my smartphone and I've had some positive results so far. If you visit the Google Sync website (http://www.google.com/mobile/sync/), you'll see apps and instructions for: BlackBerry, iPhone, Windows Mobile and Nokia. Android has Google Sync built into its operating system.
So, what's so great about Google Sync? I share my Google calendar with several people in my family and they can easily make changes to my calendar. These changes appear on my smartphone, so this helps me stay organized with my family. Google Sync can also be used in the corporate setting.
Want to learn more? Watch this short little video about Google Sync: