It was way back in November 2007 that we first mentioned Heroku, the then online Rails development and app hosting environment. It's a little more than that now - it bills itself as the "instant Ruby platform" - and you can host Rails, Sinatra, Ramaze, and other Rack apps and deploy them entirely using Git.

Today, Heroku has taken its next big step with its commercial launch. In its first two years, Heroku has been used to run 25,000+ apps and now users can pay for extended services. The free level remains which gives you one "dyno" (essentially a complete Ruby stack with a certain amount of processing power), two dynos then cost $0.05 per hour, all the way up to 40 dynos that'll put you back $1.95 an hour. You can also get extra database storage: 5 megabytes for free, then starting from $15 a month for 50 megabytes, all the way up to $1600 per month for 2 terabytes on a dedicated database box. You can play with the pricing calculator here. Features like Memcached, Workling, and AMQP (message queuing) are on the cards and will likely result in extra monthly charges.

A few days ago, Elijah Miller wrote an article about how to deploy your Rails application in 2 minutes on Heroku that you'll find useful if you haven't tried the service before. It's just a case of some work with the heroku command line client, a Rake task, and git. You might also be interested in Heroku's own Deploy Merb, Sinatra, or any Rack App to Heroku article.

Importantly, Heroku in its basic form is still free and you can go try it right now with no commitments. Congratulations to Adam Wiggins, James Lindenbaum, and Orion Henry for their efforts so far.