Miniature Mail - Little letters printed on demand and sent in tiny envelopes.
MailThis - Send mail from your computer
Send Mail Get Mail - A postcard-sending website.
The Simple Postcard - Text a photo to mail it as a postcard
DeliveryDino - Get anything delivered in 12,500+ cities!
NanaGram - Text your photos and we'll mail 4x6 prints to your Nana.