This is a good idea. You have to shift the main gear forward of the wing saddle, and add a tail wheel assembly. Sullivan and Dubro both sell good tail wheel assemblies via Tower Hobbies (and others) as pointed out by Hungryandbroke above.

On my tail wheel conversions (I've done two) and my normally set up tail wheel aircraft, I had been using their rudder follower (the tail wheel follows the rudder via linkage). But I've since just left this off, doing my steering via rudder only, which takes a little practice, but is easy to do. The rudder follower, it seems, tends to put a stress on the rudder hinges due to force applied by the tail wheel, so I just let it float which seems to work out just fine.

CGr.