Folks, there's an important issue that I'd like to draw your attention to.  This has to do with Windows 2008 RTM DNS server.  Here's a quick blurb on what the issue is:

If you're hosting a secondary DNS server with hevay traffic, what you may see is that all the records in the secondary DNS server get deleted.  This is because of a bug, which causes the secondary server to treat the zone as "expired".  The fix is available, and we want to make sure that you're aware of it and know how to fix it.

The directory services team has written a much more extensive blog post about this in their blog http://blogs.technet.com/askds/.  Check out Craig Landis' blog post here:  http://blogs.technet.com/askds/archive/2009/02/12/headache-prevention-install-hotfix-953317-to-prevent-dns-records-from-disappearing.aspx.

KB 953317 (http://support.microsoft.com/kb/953317) has the link to the hotfix that will fix this issue.