A few months ago Google rolled out Google Mobile Sync. This syncs your Google calendar and contacts to your mobile phone. On Windows Mobile, you don’t even need any software for it. It runs right through the built in Active Sync interface in Windows. Syncing happens very quickly, and it is very smart about resolving conflicts when both the mobile and on-line calendars change. I was surprised to see that Sync also pulled the photos from my phone that are associated with contacts and put them into GMail contacts as well.
Bonus Tip: When you’re using Google calendar, or a widget, use natural language to enter your events. “Lunch with Jim 12:30 Tuesday at Quiznos” Google will figure out and fill in the date, time, event and location and set up the appointment automatically.