Have you gone into ADSIEDIT.MSC and found the value of an object's pwdLastSet attribute? You'll get something that looks like 127889763885744389 which, frankly, means nothing. How can you convert this number into some date and time that means something?
Well, if you have Windows XP or Windows Server 2003, there is a really simple way of doing this because it's part of the operating system! It's called W32tm