Hi,
It sounds like the Blackberry is causing Spanning Sync to trickle
sync. You can turn of trickle syncing by pasting this line into a
Terminal window:
defaults write com.spanningsync noTrickleSyncing -bool YES
(Be sure to press return after pasting.)
Then, logout of your Mac OS X account and back in again.
That should take care of the problem.
Thanks,
Byron