Service Pack 1 for Windows XP will be officially released to the general public today, but you can already get hold of it from Microsoft on a decent speed connection. ActiveWin.com, which has been doing quite well on SP1 leaks recently, spotted this one, and as this is presumably where you'll get it when the wraps actually do come off later today, it's not likely to disappear.
Aside from 'official' leaks SP1 has been widely leaked since it RTMed. This isn't likely to have concerned Microsoft greatly, particularly as it carries payload in addition to bugfixes that Microsoft would like to get out there. It has the modifications designed to comply with the terms of the proposed antitrust settlement, the supplementary licence agreement, and the retread of Product Activation. Another leak, however, will be less welcome in Redmond - what appears to be an OEM/corporate version of WinXP with SP1 integrated has been circulating on the internet for over a week now.
This is interesting for two reasons. First, Microsoft doesn't ordinarily produce a refresh of the distribution CD with integrated service pack at anything like this speed, so it clearly wants to get as many people as possible onto the new base as fast as possible. Note however that if it gets its way and Judge CKK says the MS-DoJ settlement is cleared for landing, it'll have to stop distributing non-compliant software fast, so the legal imperative quite probably outweighs the other stuff. And second, although the source of the key that accompanies the leaked code isn't entirely clear, if it is another leaked corporate key, then the problems Microsoft faced with the original XP distribution will simply repeat themselves.
Large numbers of illicit copies of XP are Pro versions using the two leaked keys Microsoft is blocking in SP1, rather than cracked versions, so a new leaked key would just open up that particular stable door again. Microsoft will be checking keys, according to the Ts & Cs of the new licences, when users visit Windows Update, and will be blocking access to updates for compromised keys. So if the key circulating with the most recently leaked code is widely-used, it'll certainly be added to the stop list. But as the users of this code will have all of the fixes rolled up in SP1 already they'll likely only need the occasional (or weekly, depending...) security patch, so they won't be particularly worried.
The Register has seen copies of the EULA for the integrated code, and of the file accompanying it. The latter says the code is "Microsoft XP Corporate Edition, Service Pack 1 Intergrated PROPER" (which we believe may be a reference to an earlier 'improper' warez attempt), and claims responsibility for "Reformation." The EULA rolls up the supplementary licence agreements for SP1 and WMP into one piece of text, so now there's no escape. Not of course that you'd care if you'd stolen the software anyway. ®