vimtutor was extremely helpful to me when I didn't know anything about vim. It has everything in it you need to know to use it well enough to get by.
vim's very easy to use, once you know the basics.
I personally copied the vimtutor file into my home directory so I could mess around with it without worrying about ruining it or anything like that, but I think it makes a backup of it when you use it, to prevent that from happening. I haven't mastered it or anything, but I can use it very well (by my standards). I stay simple with it, even my .vimrc is simple. I just add
I haven't learned much more about it than what's in the vimtutor, though ... except for reading short tutorials on sites. I know learning more about it would be very useful, but once I could comfortably use it, I started reading about other things ...