The Toyota 4-Runner has the most common hook-end wiper arms. See sources and related links below for installation videos. Also, purchase the replacement blades first and there will be additional instructions/illustrations on the replacement packages. Locate and press the tab or button where the wiper blade is inserted into the hook of the wiper arm and pull wiper blade out of hook. You may have to rotate and flex the blade to make enough clearance for the hook to pass through.
http://www.ehow.com/how_4454148_replace-wiper-blades-toyota-corolla.html
I do not see aftermarket replacement rear wiper blades nor rear blade refills listed in the aftermarket wiper catalogs for the 2004 Toyota 4 Runner. The rear wiper was a proprietary technology/design and you may have to go to the dealer for the parts and possibly labor. Before doing this (because its usually a little more expensive at the dealer), you may want to visit some internet forums and see if there's other ideas out there. Google "toyota 4 runner forums" then search "rear wiper" once in the forums. I'm sure there's rapport on this topic. As far as front wiper blades, The 2004 Toyota 4 Runner takes 22" drivers side and 20" passenger side replacement windshield wiper blades and aftermarket wipers are available.
The 2003 Toyota Echo takes 22" drivers side and 14" passenger side replacement windshield wiper blades.
The 2000 Toyota Avalon requires wiper blades in two different sizes. The driver's side needs 24 inch blades, while the passenger side needs 17 inch blades.
I do not see aftermarket replacement wiper blades nor wiper refills listed in the aftermarket wiper catalogs for the 2006 Toyota 4 Runner. This would possibly indicate that the rear wiper was a proprietary Toyota technology/design and you may have to go to the dealer for the parts and possibly labor. Before doing this (because its usually a little more expensive going through the dealer), you may want to visit some internet forums and see if there's other ideas out there. Google "toyota 4 runner forums" then search "rear wiper 2006" once in the forums. I'm sure there's rapport on this topic.
The 2002-2006 Toyota Camry takes 24" driver side and 19" passenger side replacement windshield wiper blades.
The 2007-2010 Toyota Camry takes 24" driver side and 20" passenger side replacement wiper blades.
http://www.ehow.com/how_4454148_replace-wiper-blades-toyota-corolla.html
19" & 17"
The 2004-2008 Toyota Solara takes 24" driver side and 19" passenger side replacement windshield wiper blades.
All 2002-2008 Toyota Corolla takes 24" driver side and 18" passenger side replacement windshield wiper blades on the front.