As a newcomer to Pharo/Squeak you might expect to indent a block of code by pressing TAB/SHIFT-TAB.
As it turns out, this is not the way it works as of Pharo 1.4 / Squeak 4.3 (however this might change in the future, see comment below).
The correct shortcuts for indenting-Right / indenting-Left are:
Indent (right) Outdent (left) Win/Linux: Ctl + Alt + R Ctl + Alt + L Mac: Cmd + Shift + R Cmd + Shift + L
So: it's R/L for right/left.