I can confirm being able to successfully tether an 8330 (system 4.5.0 using Blackberry Desktop Manager for Mac) to a MacBook Pro running 10.6.2 via both USB and Bluetooth DUN but speeds are slower than when I was running 10.5. Bluetooth is about 250-300k download and 125k upload. USB is about 70k download and 125k upload. The USB connection often dips to unusable speeds (10k download).
USB network settings are Device: RIM Composite Device, Vendor:Research in Motion, Model: Blackberry IP Modem (CDMA), APN: internet.com, CID: 1.
Bluetooth network settings are Device: Bluetooth DUN, configuration: Default, Telephone Number: #777, Account Name and Password are filled with my account info, Vendor:Research in Motion, Model: Blackberry IP Modem (CDMA), APN: internet.com, CID: 1.
Changing to Model: Blackberry IP Modem (GSM) seems to be slower yet.
Verizon is still claiming they can't support Macs yet which is completely inexcusable after all these months/years of Mac users successfully tethering.