Guarding against fake Windows XP SP2 downloads

From Mary Jo Foley's Microsoft Watch: "Microsoft is warning customers not to be fooled by fake downloads purporting to be [Windows XP] SP2." What follows are instructions to tell if the download is authentic, including an MD5 checksum of the real file. There are also a few Microsoft applications that aren't compatible with the new service pack. All in all, if you're in charge of maintaining Microsoft Windows XP at your large organization, you'd better have all this figured out before you leave on any August vacation.