Any reason why you haven't upgraded your mac to 10.6.6 or is that just a typo?
When you connect the Fascinate to the USB there should be a pull down window. Select USB Mass Storage Mode. On the mac you should see an icon pop up that says "No Name." Double click that and you're in.
Now I understand the Fascinate still uses 2.1 so it may be slightly different. If worst comes to worst get Wifi Explorer Pro from the market, if you have wifi. It will get you an ip address that you can type into your browser window, and from there you can access your SD card.