“Ian Skerrett has put together quite a comprehensive list of languages supported by Eclipse and the associated plugins. In addition to that he asks anyone that notices a discrepancy in his list to pipe up and add it. I was baffled by the size of this list, but it is a great reference for developers thinking of coming over to the Eclipse IDE and thinking “Can I work in that IDE?”, the answer seems to be a resounding YES.”
Full post at the EclipseZone: Support for 20 Languages in Eclipse