[BIGGS]

If you've set up OSX using NetbookInstaller (latest tested is 0.8.3) using one of Mechdrew's guides (I used NetbookInstaller 1: USB Installation via Mac), then you don't need to use MobileBroadbandRock's HOWTO to set up your connection-- it's baked right into the Network settings under "Dell Wireless 5530 HSPA Mobile". Just enter your username and password as appropriate, and then click "Advanced...", and under the "Modem" tab, change the model to "GPRS (GSM/3G)" and enter your APN in the provided text box, and save your settings!

Easier than pie.

I've not tested this on a Leopard installation.