If you are using IMovie on your IMac then you can transfer the files by the HDMI output. You will need to review the Apple website to see if an adapter for your IMac is required. If you want to ensure hassle free combatability then check the Apple website first as they provide a list of compatable cameras. Most Panasonic's (such as kHCV100MK) are compatabile with IMac.
don't know for sure, however, I would think it should via the USB port. The iMac (or any device) should simply read the SD card as an external hard drive and allow you to capture the data. As far as playing the video off the camcorder to the iMac, that I'm not sure about. Good luck.