When someone took the time and write a tutorial like this, the least that I should do is to read it through and learn it to show my respect.
I am not totally sold on the ""Learn at least one new language every year" (p. 14 on Pragmatic Programmer book). Not that I don't think it is a great idea. I just think for one it would be very hard to do since it normally takes one (me at least) several years to learn to fully appreciate the language. Another reason is that I think it is more important to contribute back to the society of what you have learned than keep learning for learning's sake. I know I have not contribute enough as it is, given the pressure to put food on the table, making my way to afford a house in bay area, take time to enjoy life, and such.
But when all you need to do is to download the Virtual Machine and Image, and read the tutorial, and you are up every night feeding the baby anyway, why not.
Update: As it just turned out, this post showed up in case you wonder what are the choices are out there if you want to learn smalltalk.
Second Update: Free (and Legal) online Smalltalk books