You know your kid is homesick at college when... you get a hand written letter.

You know your kid is away at college homesick when... In the day of high tech gadgets and instant communication, you get a letter from them in the mail :)

The first sign your kid is homesick when they go off to college...  they write letters home!

I remember that I used to like to get mail when I was in school.  I suppose a "care" package is in order one of these days... plenty of snacks to be included for sure :)