If you’re looking for a free vector drawing program for MacOSX, look no further than DrawIt Lite.
It comes with your basic features such as your usual drawing and CoreImage filter support and a couple other types of things. Basically it allows you to get your drawing going but you won’t be able to run with certain things like “perspectives” or “beveling”.
In any case, it’s definitely a good way to take a look and see if the pro version is worth your time. I’m personally still waiting for my favorite vector drawing program to make it to MacOSX (XaraX), but I might be waiting for a long long time.