How do I find a modem driver for Mac? I'm not familiar with OS X. I'm trying to find a way to get a modem (Huawei ETS 1201, which I believe can only be connected using a USB cable) driver for OS X Leopard (on a MacBook Pro) for a friend. 

After failing to find a driver from the company's website, I was wondering whether it would be possible to use a Windows driver in any way (like some sort of Virtualization?) or whether I am likely to be able to find an unofficial driver for OS X.

TIA
First thing to check is : Do your modem support Mac OS X  ?

If the documentation said so, you should try to connect the modem directly on your Mac and see  what happens.

In case nothing works, I'd say that this modem is for PC only and you'll not find any driver for Mac OS X. 
The only way to make it works is to boot on your BootCamp partition and install the driver on it, but you'll can use only Windows and not Mac OS X.

Edit : I'm not sure that virtualization solve the problem too. Most of the time, the Internet connection is shared on the VM from host to guest. I think you can't share connection from guest to host.