Currenly, I can take pictures and video with my Canon Powershot, and then upload them to my computer's hard drive. I'd like to bypass my memory card altogether, and store media directly to my iMac.
Is there any way to do that? Would I need special camera software, or special OS X software? Are there any ways to do something similar, if not exactly this?
What you're attempting to do is called tethering. It is possible with most digital SLR cameras, but I'm not aware of any point-and-shoot cameras (such as the Powershot) which support tethering.