How would you teach a second grader how to tell time?

This first site looks excellent. The Google search page has a lot of materials that you should find useful.

http://www.fi.edu/time/Journey/JustInTime/contents.html

http://www.google.com/search?source=ig&hl=en&rlz=1G1GGLQ_ENUS333&q=telling+time&aq=f&oq=

Don't be dismayed, though, if the child doesn't learn how to tell time very quickly on an analog clock. I've seen several children who just don't grasp the concepts until 8th grade or so because they usually see digital clocks.