Hi Duane,
Thanks for the link!
Actually... Services not too far off from this do exist (though they're not free)... The US Postal Service offers it - they call it "NetPost"
http://www.usps.com/netpost/
Create it on your computer, and it gets sent through the mail!
Another service is "MoonPig" which focuses on greeting cards (in the UK and Australia)...
http://www.moonpig.com (UK)
http://www.moonpig.com.au (Australia)
I'm sure there are others too...
Cheers,
Dien