capella is described as 'With capella you can instantly create complete scores. No other notation program will take you by the hand and gently guide you towards your first own score in the manner in which capella does it' and is an app in the Audio & Music category. There are more than 25 alternatives to capella for a variety of platforms, including Windows, Mac, Linux, iPhone and iPad. The best alternative is MuseScore, which is both free and Open Source. Other great apps like capella are Rosegarden (Free, Open Source), LilyPond (Free, Open Source), Avid Sibelius (Freemium) and Frescobaldi (Free, Open Source).
GNU LilyPond is a computer program for music engraving. One of LilyPonds major goals is to produce scores that are engraved with traditional layout rules, reflecting the era when scores were engraved by hand.
Flat lets you write sheet music with your friends in real time with a nice music notation editor. Create and edit your music score documents directly with your web browser in realtime with your friends or colleagues.
Band-in-a-Box is an intelligent automatic accompaniment program. You can hear and play along to many song ideas and go from "nothing" to "something" in a very short period of time with Band-in-a-Box as your "on demand" backup band.