I meant to write about this ages ago, but now that Version 1.1 is out thanks to Thomas Oldervoll, I can happily report that I have Google Calendar working on my Blackberry 8700c!
Cut-to-the-chase instructions: load up wap.gcalsync.com on your Blackberry and install the signed version. Run the app. Choose Sync, type in your Google username and password (no idea how trustworthy this thing is) and hit Save. The Sync should commence.
Now, I had some issues with this, but it’s better than nothing, so I can only hope that Thomas will continue his work (or you’ll pitch in).
And hey, if it works for you, digg it.