I am a T-Mobile customer wanting to upgrade to a smart phone. I would like to be able to sync my Macbook iCal to Gravity Smart or Mytouch 3G. Is this possible without being complicated?
Probably the easiest way is to Sync your iCal to a Google account and then sync the phone from google. Android phones are very easy to sync with any google service and they get push notifications, push email, etc., as long as it's associated with a gmail account.
Of course, that means you have to use iCal connected with Google and if you don't like google services, you're hosed. On the other hand, if you don't like google services, don't get an android phone, most of the "best" features work side by side with gmail.
For professional reasons, I had to switch to Android phones and the first thing I did was move all my Apple stuff to Google and then sync from there. Whether you prefer iOS or Android doesn't change the fact that once everything is in Sync, the Android/Google thing works ok too.
iCal speaks CalDAV and Exchange active sync - so you have many choices to sync your phone to any server that makes sense to you.
Google calendars work well for a free solution, but it is only one of many services that you could use.