Oh boy, this should open several cans of annelids.
What are your basic computing needs? Why do you want to switch to Linux?
The best way to learn about Linux is to read, read, read, and use, use, use. The book that taught me everything I needed to know to feel [minimally] comfortable with Linux was Running Linux
from O'Reilly. Also, there is a huge amount of free documentation on the web and on any Linux machine if you can get access to one (e.g., booting a Live CD
My intro to Linux was the Wikipedia article.
Now, how is Linux advantageous over Windows?
1. It's a whole different system, so thinking of "advantages" is somewhat moot; rather, you should think about how it might better serve your needs, philosophy, or fit in better with you cognitively. I know that I feel much more in control of my computing, and like a much more competent computer user using Linux. This is not because I have to be, rather because Linux allows me to be. Linux, and Unix in general make a lot more sense to me than Windows. Someone on another forum challenged me to say "are these applications necessarily more powerful on Linux than on Windows?" My reply was "No -- I'm
more powerful on Linux." Thinking of Linux as an "alternative" to Windows is somewhat misleading since it uses a completely different paradigm of computing and has a separate history -- it was not designed as an alternative to Windows. It was designed as a clone of Unix, to serve the needs of scientists, engineers and others who demand high performance computing (as Unix had done all along, with one slight change: Linux is free software). Windows on the other hand, was designed to be marketable.
Now keeping all that in mind...
2. Linux has few of the performance problems of Windows. Furthermore, it has more secure code and a better, more up to date
set of code than Windows, contrary to what Steve Ballmer would have you believe. Independent of your needs, Linux will probably run better for what you want. There are exceptions, but if you're like me (I'm a scientist and don't play games) Linux is far superior, just because it doesn't give me the headaches that Windows did. As an example, my Slackware box at the office has been running for 19 days and 40 minutes; with Windows on the same hardware, I would have had to reboot it at least once. Linux/UNIX uptime is usually measured in years, not days.
And for people who say "You can't get that on Linux", you either can, or you can get something better (in terms of applications). LIke I said, Linux was not built as a substitute for Windows, so the applications don't carry over all that often. You can use it that way, but I'm of the school of thought who thinks you'll get more out of it if you use it the Unix way.
is a good all-around introduction to the Unix way of doing things, e.g., alternatives to word processors, using the command line. Check it out. Even an older edition will tell you stuff that will make you way more familiar with Linux.