Amy of Eat Drink Chic shares this project for DIY wedding love notes on the Once Wed blog. You can download templates to recreate this same look.
Amy writes:

This DIY includes styling and presentation ideas for ‘Message in a Bottle’ guest favors with a twist. Enclosed is a little scroll that not only contains a message to your guests but also some extra blank notepaper so that they can write a little message back to the bride and groom and drop it in a jar labeled “Love Letters” incorporated in the centerpiece design of each table.

Loveletters Wedding2