For an excellent overview of Newton's laws:
The Physics Classroom
http://www.glenbrook.k12.il.us/gbssci/phys/Class/newtlaws/u2l3b.html

For a briefer but less brilliant overview:
School for Champions
http://www.school-for-champions.com/science/motionlaws.htm

For a quiz on Newton's laws:
Thinkquest
http://library.thinkquest.org/10796/ch4/ch4q.htm

For a quick summary of the laws:
Eric Weisstein's World of Physics
http://scienceworld.wolfram.com/physics/NewtonsLaws.html

For an animation involving Newton's first law:
The Truck and Ladder
http://www.geocities.com/Athens/Academy/9208/il.html

For an interactive activity on Newton's second law:
Newton's Second Law of Motion
http://www.ic.arizona.edu/~nats101/n2.html