As another user posted, Apple are restrictive in their EULA in that the do not allow the desktop OS to be virtualised, nor do they allow OS X to be installed on anything other that Apple hardware, although it is possible.
Actually that is not fully accurate...The Snow Leopard does not cover any concept of virtualisation. The closest interpretation of that concept would be in
2.A. Single Use License - It states that you can use and run one copy at a time on a Single Apple Branded computer. One could reasonably argue that running the software in a virtual machine is not a different computer, in fact there is every reasonable argument for it that it is then the same single apple branded computer. Naturally the single use license would not be valid since you only have one copy, therefore in order to be fully compliant one could use the family pack license which is one piece of software with five licenses which paragraph in the same Software License Agreement under 2.B. does not stipulate that they cannot be used on the same machine.
In addition, if one was to use OSX Lion, when you look in the Software License Agreement you'll see the following sections;
2,B,iii - License from App Store - Allowed two instances of virtual machines on each Mac you already own or control that is already running the software. So my interpretation, if this thread was about virtualisation which it actually turned out to be not, the OP would have been absolutely fine and within his rights to virtualise the OSX Desktop on his machine. Especially considering he is not suggesting to use it in a time, terminal nor service bureau type scenario, he is popularly stated using it for personal use.
Further more it is interesting and worth noting that the Software License Agreement of OS X Lion Server (yes I know the OP was talking Snow Leopard, this is just for information) leaves out the required of using Apple Branded Computers for use by a commercial enterprise and educational institution whilst those carefully chosen words are used elsewhere in the Software License Agreement. So no such restrictions, and of course it is the same OS with some extra bits integrated and a slightly different Software License Agreement and very good value for money nowadays.