byron-sebastianHeroku, a startup that helps developers deploy web applications built with the Ruby on Rails programming framework, has a new chief executive — Byron Sebastian, founder and former chief executive of open source company SourceLabs.

Sebastian and co-founder James Lindenbaum describe this as a normal startup move, where a company brings on a more experienced executive to lead the team as it’s ready to grow into a big business. In addition to founding SourceLabs, which was acquired by EMC at the end of last year, Sebastian has served as Vice President and General Manager of BEA’s WebLogic portal and Vice President of Product Management at Crossgain.

Heroku offers a platform to take the headache out of deploying and managing Rails applications. Once you’ve built the app, just launch it on Heroku, which scales your computing capacity, memory, and storage as needed. (It uses Amazon’s cloud infrastructure.) The company says it now hosts more than 35,000 applications and has been growing at a rate of 50 percent every month since launching. It started charging for its service in April.

Sebastian says one of his big goals as CEO will be making sure Heroku is well-suited for the large companies who are starting to show interest. One of the most promising things about the company, he says, is the fact that it’s using the Internet cloud as not just a different business model, but as a way to transform the way applications are deployed.

“I think that slowly people are beginning to understand what a cloud platform as a service means,” Sebastian says.

Heroku has raised $3.5 million from Redpoint Ventures, and was incubated by Y Combinator.