A few weeks ago I discovered Google Calendar Sync. It syncs the calendar on my blackberry curve with my online Google Calendar.
"Using your BlackBerry smartphone's native calendar, you can now access your Google calendar even when you don't have network coverage and be alerted for upcoming appointments with sound or vibration. Your Google Calendar stays synchronized whether you access it from your computer or your phone. You can add or edit entries right on your BlackBerry smartphone or on your Google Calendar on the web."
This then syncs easily with iCal on my Macbook Pro. Its a good thing I use a mac because I couldn't find any easy or free way to get my Google Calendar to Sync with Outlook.
The application can be downloaded by visiting http://m.google.com/sync on your blackberry. It supports any Google Apps accounts.
In my opinion Google has some of the best mobile apps, including maps and gmail. This is why I am so excited about Android.
All my calendars are always updated and in sync and can be accessed and edited virtually anywhere I am.