Thanks for the suggestions:
Equipment...You can buy keyboards with very accurate sounds for all brass, reed and percussion instruments.
I have a keyboard. It's kind of old, but has Midi output. I've never really understood how that aspect of it worked, though. I'm not really into having a keyboard that sounds like the instruments. I just want to be able to get by so that I can write the music for an actual marching band...not to create the sound myself.
I know of freeware for drums, but I'll get to that later.
Drums are a whole new ballgame. I'd probably have to go over some Sousa pieces and stick closely to hit beats.
Dave, you need the program called Finale. its the best program to fit what you described above. its also VERY simple to use. its basically just a midi sequencer, but it has a graphical sheet music interface, so as you play the notes, they pop up as actual written notes. you can do a whole score, and have the computer make seperate parts for each. it will even write out the correct transcriptions of any instrument if you wanna print out a copy for a friend who's a trumpet player or something. it enables you to write the whole piece in just 1 key, and let the computer do the transposing. its a nice piece of software....check it out.
This sounds cool, but does it have any semblence of playback so I can hear the different parts laid over each other?