Sending a card is easy. You can purchase gifts or gift certificates through online merchants to attach to your card. You can attach video, voice, or photos to your cards for free. You can specify the date the card is to be sent up to a year in advance. Gifts are also available.
Every free card sent helps generate a donation for the environment and wildlife.
Several options for customization. The Electric Postcard A bare bones no frills site. Very simple and easy to use. You can add HTML to cards if you like. The cards are apparently public domain images but are beautiful and unusual.