http://www.betanews.com lists updates and beta software by date along with news about software and software vendors.
http://www.fileforum.com is frequently referenced by BetaNews as a download location. It is, itself, a good site for Windows and Unix updates and downloads. Files are categorized and date-sorted.
http://www.majorgeeks.com seems to be a little more technical. Information is recorded chronologically.
http://www.versiontracker.com has sections for Windows, Palm, Mac OS and Mac OS X and has a Pro (paid) version