The Sibelius Group has released Sibelius 2 for Mac OS X.

Sibelius is a real-time music notation program, capable of writing musical scores for 150 or more instruments. There's a review of a previous version here.

Ron Okamoto, Apple's vice president of worldwide developer relations said: "Sibelius 2 is a valuable music notation application."

"Sibelius is more elegant and beautiful than ever, with a new look which complements Mac OS X's stunning Aqua interface," said Ben Finn, CEO of the Sibelius Group.

Sibelius 2 for Mac OS X offers 200 new features and a number of enhancements. New features include Arrange, which lets musicians use their Macs to arrange and orchestrate music automatically. It's the first commercially available music application to offer this facility, the Sibelius Group claims. In use, a composer can automatically orchestrate a complete piano piece for a concert band, for example.

Note input has also been improved so users may use every feature of the application without a mouse. Audio playback has also been enhanced. Colour support has been improved – it's possible to import coloured graphics into the music with this release.

The Sibelius Group has also announced PhotoScore Professional 2 for Mac OS X; an improved version of the optical music recognition software developed by Neuratron that enables users to scan printed music into Sibelius 2 software. It's the advanced, faster and more accurate version of the PhotoScore Lite scanning software that ships with Sibelius 2.

Once music is scanned, read and sent to Sibelius, it becomes a fully editable Sibelius file that can be transposed, re-arranged, played back and printed. The application costs £595.