There is now a beta version of the UV200 Mac driver that is compatible with Snow Leopard. It supports the 32-bit kernel but doesn't yet support the 64-bit kernel (only loaded by default on the Xserve). You can download the beta driver here:
http://support.trittontechnologies.com/supportsuite/index.php?_m=downloads&_a=viewdownload&downloaditemid=62&nav=0,3,7
Checking if Snow Leopard is running the 32-bit or 64-bit kernel
If you are not sure which version of Snow Leopard you are running, you can check by following these steps:
1) Select About this Mac from the Apple menu
2) Click on More Info to open System Profiler
3) Click on Software and check the “64-bit Kernel and Extensions” option. If you are running the 64-bit Kernel, it will say “Yes”, if you are running the 32-bit Kernel it will say “No”.
How to Switch from 64-bit to 32-bit Snow Leopard
If you found that your computer is running the 64-bit version of Snow Leopard, simply restart your computer holding down the “3” and “2” keys on the keyboard to load the 32-bit kernel.
