In looking over some of my old numbers of Martha Stewart Living, I found a great article on making Seashell Valentines in the February 2003 issue so went to check her website and found one of the valentines there. There were more ideas in the magazine itself so if you like the example in the link below, you could always borrow the magazine from your local library.

Seashell Valentines (it took a while for the page to load so you might have to be patient)