Creddon - Tweet for a cause and a sponsor will donate $1 to charity
Postacard - Text a photo to send it as a postcard for $3.
All or Nothing - Competitive donations for causes you care about.
Felt for iPhone - Handwritten cards for the modern world
Public Design Vault - 500+ design tools for public good, all in one place
NanaGram - Text your photos and we'll mail 4x6 prints to your Nana.