The successor to S3M2NSF. It converts IT files to NSF files. The IT files must have special MML data in the song message. The MML data describes how the instruments will sound (including duty envelopes and such!), and the layout of the module channels. The program also has a special feature which generates 'preview' instruments inside an IT file so you can hear what you are composing. The instruments are multi-sampled at different octaves to have an accurate sound at any pitch. All of the NSF expansion chips are supported!
Link to download here: http://mukunda.com/projects.html