The CMD code is copyrighted, but it simply deletes the "Domains", "EscDomains" and "Ranges" trees in all three places where Spybot adds its entries (SpywareBlaster uses one of those as well), then recreates them--empty, of course. Basically, it deletes the 10,000-plus entries Spybot (and SpywareBlaster) added in each tree.
Please note that after you run it once, you do NOT have to re-run it after each immunization IF you simply uncheck all of the "Domains", "IPs" and "Secure Domains" entries for IE on Spybot's Immunize page; you only have to do that once. (You may also want to check the "Do not show this again" box on the post-immunization pop-up warning.) You do NOT have to undo hosts-file immunization.
If you also use SpywareBlaster, just don't use it anymore; I don't know of any easy way to keep its updates from affecting those keys, and most of its other tools are available elsewhere (including Spybot).
I can confirm that it does reduce the hangups in IE8, though it's still not as fast as IE7 in that regard.
However, Microsoft should still be called to task for this. It may not be "supported", but they've certainly known for a long time how Spybot & SpywareBlaster work; it was WRONG for them to break it that way, and even MORE wrong for them to defer any fix till the next IE. It could be read as Microsoft breaking a competitor's software, which ought to get them in trouble with the EU again...