Miniature Mail - Little letters printed on demand and sent in tiny envelopes.
Felt for iPhone - Handwritten cards for the modern world
MailThis - Send mail from your computer
Thankster - Automagically send hand written cards
The Simple Postcard - Text a photo to mail it as a postcard
Handwrytten - Handwritten notes straight from your device. Huge selection of cards or design your own. Handwriting service integrates with 1000's of apps.