Tadpole, could you please elaborate a little more on how to go about making the batch file to preview the songs?

yeah, make a batch file that will compile.  As you edit the song and want to hear how it sounds, push CTRL +S in notepad to save.  Then double click the batch file to compile. 
I have winamp + chipamp up so then I double click on the song in winamp and listen to it... hitting the arrows to scroll through the song until it gets to the part I want to hear

No you can't convert GB to MML

Also, is there a way to rip a commercial GB rom and convert it's audio to MML to analyze it?

I'm using XPMCK to compile the MML into ASM for use in the game, but is there a good way to preview the GameBoy MML before compiling it and loading it into an emulator? Does XPMCK offer playback or just compiling? Because I didn't see anything on the site or in the program.

XPMCK is how you write gameboy music with MML.  It's a bit buggy though. 

http://jiggawatt.org/muzak/xpmck/

I've decided to use MML and already have most of the song structure finished. I've been using http://www.mmlshare.com to preview the music, but is there a better way to quickly test things? MMLshare seems more designed for the NES as well. Anyone else make GameBoy music in MML have any tips on programs to use for Gameboy?

mml looks difficult at start
but it is easy if you already have the song structure
you just need to translate it to the mml format after that

composing in mml is a different story
it makes you think in time intervals, which is great

I have a few Game Boy music engines that I've received from specific commercial game coders that import XM/IT and have their own instrumentation formats.  I'm in the long process of making things a little more use friendly and adding the ability to export GBS.  Not releasable at the moment and maybe not for a while.

was just gonna post a bunch of links, but heres a page with them already there!
http://battleofthebits.org/lyceum/View/MML/

strolling through this might help: http://pdroms.de/news/gameboy/

and from the (always handy) woolyss resource: http://woolyss.com/chipmusic-mml.php

MML

here is a music album which was done in MML, the ROM is available for download at that link.  it may help taking a look at it.

LSDJ is bad, cause it uses almost all the cpu for music. +1 Carliion or even MML.

dude your idea is awesome! please message me when its done! i wanna buy it!

I think Carillon Tracker might be a good tool for this, or maybe Paragon5.

I don't think that LSDJ has an export code option, the tracks are only re-playable on LSDJ actually.
Maybe you could wait to the release of DefleMask with the ASM export enabled.

I'm making a "homebrew" game, and was curious what would be the best way to write music for the system. This is a real game that runs on a GameBoy. Any idea how the game developers did this? I've heard there wasn't an official dev kit or software until the GameBoy Color era, which I think explains why there weren't many "voice" samples until that time.