Apple machines still are incredibly expensive in Brazil. Like most other computer items, they cost 3-4 times as much as in the United States, an unfortunate consequence of the infamous "Brazil cost" : a combination of incredibly high internal taxation, bureaucratic costs, and tariffs on imported goods, particularly electronics. I'll write more about that later.
This Samsung Blackjack is a Windows mobile 5 device, and technically does not work with Mac OS. This blog post, and this one explain how to make it work using a Blackberry connection script.
I found them a bit confusing (being new to the Macintosh), so I'm correcting the instructions a bit according to my experience, and adding a couple more screenshots. The instructions here are for Cingular. I suppose this would work with other carriers if you get the username, password and "number" to be called.
1) Make sure you can access the internet through your phone. Go to Start -> Internet Explorer and navigate to some known website. I had to go through support after the phone was activated for it to work, and even after they fixed it, it wasn't a few hours had passed that I was able to access the internet through the phone.
2) Download the Blackberry 3G Driver
3) Unzip it.
4) Open a new Finder window by double-clicking on "Macintosh HD". Navigate to Library -> Modem Scripts
5) Drag the three CID files from the zip to the Modem Scripts folder (BlackBerry 3G.CID1, .CID2, and .CID3
6) On yout phone, go to Start -> Settings -> Connections -> USB. Change it to Modem
7) Connect your Blackjack to the computer with the USB Cable
8) On you Mac, click on "apple" (the blue apple on the top left corner of the screen") -> System Preferences -> Network (alternatively, search for "network" on Spotlight, the blue magnifying glass on the top right corner, and click on the "System Preferences - Network" item)
9) Click on Location -> New Location. Enter a name for the connection, such as "Mobile"
10) Click on Show -> SAMSUNG CDMA Technologies.
11) Under the PPP tab, enter the following:
Service Provider: Cingular
Account Name: WAP@CINGULARGPRS.COM
Telephone number: WAP.CINGULAR
12) Click on the PPP Options... button and enter the settings as in the picture.
13) Click on the Modem tab, the on the Modem select box and pick the Blackberry CID1 or CID3 entry (CID1 worked for me)
14) Click on Apply Now
15) You should now see the little phone icon on the menu bar. Click on it, then click on Connect
With some luck you should now be connected. I did a little speed test and it wasn't bad: 934 kbps down and 177 kbps up.