First, yes, WM is not compatible with OSX. In order to sync a WM phone to OSX, you need to use a program called 'MissingSync'. Here is the version for the BlackJack II:
http://www.markspace.com/products/windowsmobile/mac/windows-mobile-sync-software.html
It's a decent program, about 30 dollars, but I think it's worth it. Just a heads-up though, trying to integrate with OSX and WM6 is a massive pain, so don't expect stellar performance. This being said, keep your expectations low.
As for tethering, it can get you in trouble, and it is definitely not an easy thing to do, but here's how to do it anyway

. I was wondering the same thing about 6 months ago, figured it out after much frustration, and wrote a guide for personal reference with the intention of one day submitting it

.
So here ya go:
How to tether your BlackJack II to your Mac
Disclaimer: Please note that if you dont have a tethering plan and if AT&T catches you using massive amounts of data, you will get busted and slammed with a massive bill. I assume no responsibility for your actions. This being said, have fun!
1.) On your BlackJack II: go to
Settings-->Connections-->USB
2.) Change the USB connection setting from
ActiveSync to
Modem.
This allows your BlackJack to act as a modem. Note that under this setting you cannot use syncing services. If you want to return to being able to sync, all you need to do is change the USB connection setting back to
ActiveSync.
3.) Plug the BJII using USB to your Mac
4.) On your Mac open up
'Network Preferences' and it should see the device on the left. Click on the Samsung device.
5.) In that menu, hit the
Advanced button, bringing up a new screen
6.) Change the Vendor name of the Modem from
Apple (default), to
Samsung. Use my following picture as a reference.
5.) Now enter the following settings.
Telephone Number: *99#
Account Name: WAP@CINGULARGPRS.COM
Password: CINGULAR1
Note that everything here is cAsE sEnSiTiVe (yes, everything is in caps). Use the next picture as a reference.
If you want, you can also check
Show modem status in menu bar. It's convenient to see how long youve been connected.
7.) Hit Apply, and then Connect!
Enjoy your 3G internet from your BlackJack II now on your Mac!

You can get DL speeds (at best) of 100KBytes (not bits!

)/s. Don't expect it to be reliable though.
----
Note that you cannot tether and use MissingSync at the same time, since you have the phone set to
'Modem' rather than
'Active Sync'. To use MissingSync, simply switch back to
'Active Sync'.
If you happen to have USB trouble connecting back to MissingSync (which you probably will), you may need to add a program called 'USB Killer' to your phone, which will force the phone into
'Serial' mode, which for some reason allows MissingSync to detect your phone if you happen to have problems.
Overall, tethering and syncing to a Mac with a BlackJack II is
not an easy thing... it's a massive pain in the ass, but until I have enough spare cash for an iPhone, it's the only way to do it for my BlackJack II.
I hope this helps!

let me know any kind of feedback, I want to know whether or not it works for you.