I didn't know that and I was exciting to heart that.
But after I read the page, it's not the all story.
"Beginning November 1,
new AWS customers will be able to run a free Amazon EC2
Micro Instance for a year,..."
It only offers for one year.
So, the hope of this webapp has run away once again. ;p
About the charging, I wouldn't do so if I really write one. It's unfair to Gmail (not because they won't earn potential money) or to people who need to see the large emails in my opinion. (It's hard to explain why, so don't ask)
I really wish I could help on this issue more.