In order to get the source code for ASM, you will need to have Subversion installed. To build the source and run the tests, you will need a JDK supporting Java 1.5, and Maven 2.
The source is in a pre-release stage and only accessable by MPC members. If you're really interested in taking a look at the code, drop me a email at dstovall@mail.utexas.edu and I'll send you a copy.
svn co svn+ssh://username@mpc.ece.utexas.edu/svn/asm