Well, I started this thread a DECADE ago! I've had many machines (mills, lathes, surface grinder, etc) and moved each into and out of my garage, even moving houses a few times. I just finished putting together a video that answers a lot of the questions I had 10 years ago - about how professionals move machinery without breaking a sweat. I tried to edit in a way that helps anyone new starting with a retrofit project, or even just buying a manual machine for the garage. A lot of the basic techniques (toe jack & machine skates) are easily accessible to hobbiests on the cheap - either by making or renting these tools. I also highlight why someone might consider paying for a rigger, even when professional rigging seems very expensive compared to the purchase price of a used machine.
Actually, I have a few other videos about machine moving. If you're interested, you can look at my channel. Among the videos, I share the shop-made machine skates and toe jack I built to move machines around the garage at will.
Hope it's useful to a new generation of DIY machinists. =)
my blog: http://www.mechtopia.com/blog