I’m looking for a program silimar to Finale Notepad (where you can plug notes onto a staff and all) but that can also work with making ABC formatted files readable. I need the thing where you can compose music on a program to transpose music for choir and praise band, and I’d like to have the ABC thing so I can also use the program for whistle music. Any advice for freeware programs I can look into or at least decent demos? I tried Melody Assistant, but the demo version didn’t allow me to write music in bass cleff. Bleh 
For the price ($40), Noteworthy Composer is great for composing music and plugging notes onto the staff and playing it back. Transposition is a simple task with Noteworthy. It doesn’t read ABC directly but can import midi’s. There is a free utility called abc2midi (available elsewhere) that will convert ABC to midi which can then be eaisly imported into Noteworthy. Alternately, you can use Concertina’s web site to convert ABC to midi.
Here a link to a simular set of posts regarding notation.
<a href=http://chiffboard.mati.ca/viewtopic.php?topic=1426&forum=1&6>Including my comments on Melody Assistant
Melody Assistant does all the things you mention, and is share ware, registration is $15 and well worth it. It does midi, ABC, and you can create a 10 part score, assign a different midi voice to each part, and then play it back. It easily transposes scores. It is what I use transcribing music.
Hope this helps and …