The tutorial is over at Mique's ThirtyHandmadeDays, at this link. Allison, a guest writer, also includes a file you can download for the little cards to go with them. Each of the four designs has different wording.
These can tuck into a card for mailing or giving, as well.
Although she uses a hot glue gun, I'm sure other adhesives would work as well if they claim to bond to felt.
This project was found in one of my daily e-newsletters from CraftGossip.
This is part of my series (1/15-2/14) of Valentine projects.
For other projects in this series, just look along the right sidebar for the label "Valentine Projects." I will post only tips that do not require knitting, crocheting, machine sewing, tatting, embroidery, or any other skilled technique.
If you are feeling lazy, check my Etsy shop for items for your gift list.