I've put the new 2.4 alpha (not even beta yet) source code on the FTP. If you want to see it, you'll need Visual Basic (also available) and compile it. You need to copy the fastmath.dll in the fastmath release directory to windows/system. If you don't, the program can't run.
When I figure out the packaging thing I'll release the compiled program to the FTP.
Everything works in it (or anyway should) except the mutation code. The number of changes are immense, I don't even know where to begin. Most notably the physics engine is redone. DNA routines have also been redone, and even some new things added. You'll have to just look around and see for yourself.
Other neat tricks. I don't even remember. By all means post if something looks screwy, the amout of code changes is just enormous.