Microsoft Windows ISO checksums

An MSDN subscription is not needed to browse the contents on the Subscriber Downloads page.

Once there, you can browse to any product and click on the Details link to see the SHA1 hash for the product

for ex.: Windows XP Service Pack 3 (x86) - CD (English)

Windows XP Service Pack 3 (x86) - CD (English)
SHA1: 8fa76ccea145d050fc6a506ffbdedfe53282e5b4