The download ranges from 203mb to 615mb, compared to the full source code size of 40gb. However, Microsoft's noting of this is merely an attempt to downplay how much of the code is actually available. The full 40gb of code includes the code of all Windows-compatible programs, along with millions of lines of comments and other erroneous material not having a direct effect on the code. This was cut out, and it is believed by people in the open-source community that a majority, if not entirety, of the code (kernel) is available for download. Note: If you don't know much about source code or programming or Windows, etc., know that the availability of Microsoft's Windows source code is a big deal. Already being an insecure and vulnerable OS, Microsoft has always claimed security through obscurity by keeping their source code private and copyright protected. There have been instances when parts of the source code have been obtained, but never the full code including the kernel. Because of this, there is much speculation as to what the consequences may be, and also regarding how this came about. Due to certain text in the source, it is believed that a programmer at mainsoft used a program called VI IMproved 5.6, which is used to edit programs, to make the code available. Mainsoft was granted access to the strongly hidden source code in March of 2000, in order to create a Windows platform for programmers to use on Unix systems. However, there is also the 'conspiracy' speculation going about that Microsoft may have helped leak this code in order to profit from the DTS patch and their new OS being released next year. Regardless, many of us are holding our breath until we see the full consequences of its widespread availability. There is a potential threat of hackers world-wide finding holes and back doors and utilizing them before Microsoft has any opportunity to patch them. If this were to happen, the consequences could be cataclysmic due to the global use of Windows OS 2k and up (which are based on the 2k kernel).
There are torrent links showing up and disappearing spontaneously all over the net. If you're curious and/or want some bragging rights, go to the link provided in my journal and start downloading. However, take note that having the raw source code in your possession is (I believe) illegal - or at least uploading it is. If you're a programmer, you'll obviously be interested as well. However, if you are a programmer, know that if it's ever discovered you viewed the Windows source code and are working on developing anything outside of Microsoft, you'll find yourself unemployed in a heartbeat.