I have to add another plug for Tom Chapin's "family stuff." In particular, check out "State Laughs" and "long Way Home." These are fairly easy to pick up and the kids love 'em. I do the above with my 4th graders and have also done "Billy the Squid" (In the Pink Coral Lounge-that's a sand bar...a beautiful mullusk, a real living dollusk, her name was Clamity Jane..."). :-)
Don't forget Bill Staines' "All God's Critters". Also, check out Red Grammer's kid's stuff.