<p>Just tap <tt>CTRL+TAB</tt> quickly to switch between the current and the last application/window. Or press <tt>CTRL+TAB</tt> and hold the <tt>CTRL</tt> key to go through all running applications by repeatedly hitting <tt>TAB</tt> or <tt>CURSOR LEFT/RIGHT</tt>. If you need to get to a specific window of a program, move to its icon as described and then go through its open windows with the <tt>CURSOR UP/DOWN</tt> keys.
<p>It's also possible to invoke the Twitcher with <tt>CTRL+TAB</tt> and then use the mouse to choose the application/window you'll jump to when releasing the <tt>CTRL</tt> key.