I've had a lot of positive feedback from readers for including Heroku in Learning Rails. Its web-based interface is the easiest way I know to get started with Rails programming without getting trapped in installation challenges.
They're changing gears a bit now, though, as they move into the business of selling Rails deployment. I'm happy to report that they still have the free web-based Rails interface, but it's moved to a new URL: herokugarden.com.
I'll be updating the errata for Learning Rails as well as the First Steps into Rails (on Heroku) screencast as soon as get a moment!
I'm also looking forward to exploring their deployment options. Phusion Passenger (aka mod_rails) made deployment a lot easier for me, but just switching the application on seems even nicer.