Well, I was in your position a few days ago, so assuming that your card actually works with the Zaurus, it shouldn't be hard to set it up. Are you sure that the card is compatible?
I have the Japanese version, so I'm not sure of the exact English names for things, but you need to go to the Network Settings in the Settings tab. Click "Setup" and then follow the prompts. Actually, it's quite easy (and this is coming from another Mac user).