I second Fuji - get the G1000 CD ($20 or $25? don't remember) for the actual aircraft you will fly, all G1000 installations are subtly different, except for the Cirrus installation, which is unsubtly different. It is also cheap.
Then download the G1000 training guide, which contains two dozen or so "lessons", and work through it. While a bit mis-named and not that great (it looks more like a test) it makes sure that you cover most areas of it's functionality.
Can't comment on the other recommendations, they migt be worth checking out, too.
One word of warning: When you "load" and "activate" instrument approaches, monitor the system like a hawk. The G1000 automatically dials and selects approach aid frequencies, exactly when and how depends on what is displayed on the HSI. It works very well if you fly the "Garmin" way (GPS/FMS all the way until you intercept the final approach track), but can b**er you up when you select and use "classic" navaids yourself.