Books on Smalltalk abound. All describe dialects that vary somehow from Squeak. The oldest books may be best since they describe the roots from which Squeak grows.
Websites for classes using Squeak. Examples: assignments, tutorials, cases, etc.
http://pbl.cc.gatech.edu/cs2390/1.html – the main class website. Lots of stuff here – over 75 fully worked out and documented Squeak programs. -sorry dead link-