Free API Infrastructure is definitely a cool thing and we've been doing it from day one - our thoughts here <a href="http://bit.ly/OY7mLN" rel="nofollow">http://bit.ly/OY7mLN</a> :). Welcome to the party Apigee!
One thing to be aware of: once you've reached the 3,5M/month limit of the Free then you have to move to the Enterprise solution that starts at $9,000/month !!