For the romantics...

Have cupid send your Valentine's Day greeting card (or any other
romantic card) to your sweetheart that bears a postmark from
Loveland, CO 80537. This city is one of several cities that has a
special name whose postmark can embellish your greeting card
with romance.
Special postmarks say, "I love you" because your partner will know that you extended some extra effort to make your greeting special.

Send your Valentines through Loveland -- remembering to afix the
appropriate postage -- and postal officials there will cancel the
stamp with hearts, a cupid or some other holiday theme before
sending it on to your sweetie.

There are more POs at this website for a variety of postmarks:

http://www.celebratelove.com/valpostmark.htm

Not sure if I did a proper "blicky". Maybe this:

http://www.celebratelove.com/valpostmark.htm

Or you can paste the first one into the URL window.

I hope everyone has a wonderful Valtines Day. (I'll probably be alone, but who cares about my little troubles. ;-) )