First, a little on what this can do:
Over the past few days i've been working on a little project that makes new bipeds A LOT easier.
From max to Halo in about 2 minutes:

(That ATV is a WIP SSDC is working on)

(That Pelican is a WIP SSDC is working on)
The biped was extracted and rigged in max using the skin modifier by JamesD. I then used a program and maxscript that i made to export the vert weights from max into a gbxmodel tag.
I, knowing nothing about rigging bipeds in max, managed to rig Neuro's Barney model (somewhat roughly) within about 20 minutes, then exported that straight out of max, into halo, again just a 2 minute-ish thing.

That was just for laughs

Skin modifier is the way professional character animators rig up models to bipeds/bones. You don't need to break the obejct into mutliple different parts. Its all one model, you then make a biped structure like the MCs, place it near enough inside your model and then do skin modifier on the object (its in the modifer list) you then add all the nodes by hitting the add button, select all of them other than Bip01. You can then hit edit envelopes to control which bones affect which vertices and how much by - you can see the results right there and then in max so there's little trial and error - what you get in max is what you get in halo!

The program/maxscript:
You need the .NET Framework to run the app
http://www.microsoft.com/downloads/Than ... layLang=en
Instructions:
I will post a tutorial on rigging a biped using Skin modifier later, for now use google or 3ds max help to find out how.

Exporting from max:
Make sure your model is selected, and the Skin modifer for the object is selected in the modifier stack. Run the script:
http://computernova.com/VWM/weight_export_08.ms
Save it out to a file that you can remember/easily access.
Now, export the object from max as a .jms and compile it through tool in the normal way into a gbxmodel.
Now go into guerilla, open up your new gbxmodel tag, and hit File > Export, save the .txt as something again, easy to access.
Injecting into GBXModel
Now open up the Vertex Weight Injector program. (.NET Framework required)
http://computernova.com/VWM/VertexWeightInjector.exe
Now, drag the txt file that you exported from max into the appropriate box, and then drag in the txt file that you exported from guerilla into the other box. Wait for the message box to come up, and then save the file to a .txt.
Then go back into guerilla, close your old gbxmodel tag that you had open, and hit File > Import and import the .txt file that you just saved from the Vertex Weight Injector.
Enjoy!

I'll post a more in depth tutorial soon. Have fun, and report bugs in this thread.

This is only the first version (well technically version 0.1

I will be working on a gmax version tomorrow most likely.