There are a fair number of Smalltalk tutorials on-line, though they vary in quality. (Please add your ratings here.)
On this Wiki:
Smalltalk Tutorial (might could use some improvement?)
On Visual Works's Wiki:
wiki.cs.uiuc.edu 
On Squeak Smalltalk's site:
squeak.org
On Dolphin Smalltalk's site:
More directly:
www.object-arts.com
See original on c2.com