Yesterday I bought a USB modem for 3G access. I hopefully will get easier access to Internet when I need it than when using a USB cable to an LG phone. Fewer things, no need to make sure “the phone” is charged all the time, and more stable drivers.
Hi3G in Sweden (that I have a subscription with for 3G data access) have the Huawei E220 3G USB modem for sale, and drivers for MacOSX exists. It is though important you really read the details in the instructions, including that you run the two install packages in the correct order. They are named with prefixes “1” and “2” on the file names, so it is not so hard.
The connection is flawless, and it “just works”.