Personally I haven't tried it, but you might check out EPals Classroom
In a message dated 7/21/01 11:49:10 PM, firstname.lastname@example.org writes:
>Have any of you had success with art penpals? If so, where did you go to
>find other art classes willing to do this? I've thought about it for a
>year or so, and think this would be a great idea, but need some ideas on
>starting out. Maybe there is someone across the country (or even close
>by?) that would like to get in contact and we could exchange artwork.
>(I teach middle school in Burbank, Ca.)
>Thanks for the help!