I am considering getting the 970 but I am worried about doing firmware updates since I am a mac person and do not have a Windows PC. First question. If I get the 970 in the next month or so, will it come with the latest firmware update already installed?

Second Q: What do I do for other, later updates?

You may want to call and check with Outlaw on what version of the firmware is currently installed on units when they ship (they generally ship with whatever the latest version was when they left the factory).

Assuming you can't use Boot Camp or some other method of emulating Windows on your Mac, the best bet would be to borrow a PC laptop (or desktop, although a laptop's more convenient) from someone to install the firmware. It doesn't need to be anything new or powerful, just something with a serial port and Windows installed. Heck, let us know where you are and there may even be a gunslinger nearby who could lend a hand.

Actually, I just got my 970 about 2 months ago and was told that they ship with the stock firmware (no updates). I ran it the way it came for a month, then upgraded.
I am interested in upgrading from Linux, which has been promised (there's no mention of Mac). Although I was able to run the install program in Linux using the Wine emulator, I did so without actually connecting the serial cable afraid that I might end up with a brick. I ran the actual upgrade using my kids' Windoze box.

If you have one of the intel macs, use bootcam and install windows as a secondary os for wneh you need these types of things. if you have a g4, g5, you can run windows vitural pc to do the update.