Here's how we do a Macintosh "jump start" at my company.
1. Hie thee over to Amazon and do a search on: Apple Training Series
2. Have your company score you a copy of the latest editions of:
- Apple Training Series: Mac OS X Support Essentials
- Apple Training Series: Mac OS X Deployment
- Apple Training Series: Desktop and Portable Systems
3. (optional) If you have a decent UNIX background, also check out this O'Reilly title: Mac OS X For Unix Geeks
Then do the "JumpStart Boogie":
- Get permission (if you need it) to take the MacBook home over a long weekend
- Stock up on your "favorite poison" and some healthy snacks
- Give each of the books a quick skim
- Buckle in, get working.* Do focused topic reading as needed.
(* Mess with it, Break it. Reinstall it. Play with it!)
By the end of the weekend you'll be more knowledgeable than 75% of the people calling themselves "experts on the Macintosh." After you get 3-6 months worth of 'live' support experience, you'll blow the doors off 90% of them.
<Edit:> Almost forgot to mention the most important thing. Be sure to have fun
while you're doing all this. For all their shortcomings, Macintosh computers are interesting devices, even if you ultimately decide they're "really not your thing."