Structure and Interpretation of Computer Programs in tagged and optimized PDF version is available here. The book is the basis for computer science course 6.001 at MIT and quoted by Joel Spolsky's rant about the dangers of Java Schools. You could read this book on your PDA and code away on or cut and paste the samples using the brilliant Pocket Scheme for an extremely geeky tour de force. By all means buy a copy of this unrivaled classic, also to get the famous wizard cover that’s missing from the PDF:
Milos: Thanks for this great post! Do you have the possibility to fix pages 108 and 426?
hale metalice: Glad you like it, glad to get some bloody feedback for a change : )