GCalSync: Sync your cell/mobile with GCal
GCalSync is an app that offers two-way synchronisation between your mobile/cell phone or Blackberry and Google Calendar.
You can download events from GCal to your mobile phone and upload events created on your mobile, although at the moment, changes made to events on your mobile are not synced.
The past and future date ranges are user-customisable.
Currently the app does not support reminders and treats repeating events as multiple single events, but the developer promises more features soon.
Lots of Nokia handsets are supported as well as many Sony Ericsson models and two Motorola phones (not my RAZR, however, hence no screenshots).
You can read more about it and download the app on the developer’s web site 
or just point your phone at http://wap.gcalsync.com to get started.
Related posts
January 15th, 2007 at 1:07 am
Of course, gcalsync is for Java based phones. For windows mobile phones, there is OggSync which has a free version that supports:
* Full 2 way sync from your phone to one of your Google calendars
* Supports Google Hosted Domains
* No 3rd party involvement, keep things simple with just your phone and Google Calendar.
* Full support for repeating events, and changes to those repeating events
* Uses over the air or cradled connections so you can always be up to date
* Compatible with Outlook and ActiveSync
Best,
- OggSync