My boys (ages 17 months, 4 & 6 1/2) love cleaning with a damp cloth - they love rinsing the cloths- and cleaning the baseboards, doorknobs, doors and walls. With three boys each has a different outlook on what clean actually is, but the sure enjoy working together, even if it does mean a change of clothes is in order afterwards!
There are various cleaning wipes/products that are easy for them to use as well, but just be careful to find those that are age appropriate and won't harm them (skin irritation, if they put things in their mouths, etc). When in doubt, stick with water & a clean wash cloth!
Also, if you haven't already, making a chore chart for them helps. This site, http://www.dltk-cards.com/chart/ has some simple, FREE, custom charts you can build. Or you can google "chore chart" and find tons of options.
Good luck!