I was updating my BlackBerry apps and noticed that Google Sync for BlackBerry now includes Google Contact synchronization. You can upgrade from Google Mobile Apps on your BlackBerry (select the "More" option, highlight the Sync icon, and choose upgrade), or you can visit m.google.com/sync from your phone and install or upgrade.
I am using a BlackBerry Curve 8320 and OS 4.5. Google Sync does two-way contact and calendar sync and it is working for me. I am very happy to finally have contact synchronization.
I had just signed up for Soocial, but their BlackBerry sync is still missing.
This move from Google is welcome; I was beginning to think they only love the iPhone and forgot us BlackBerry users. :-D