This has been kept under wraps by the Operating System and Hardware vendors for the last few weeks and now patches have finally been released for many Operating Systems, DNS software applications and Hardware devices.
If you provide or rely on DNZ services (external and Internal) you should consider quickly patching your servers/devices.

Although Internal DNS servers may not be exposed to an Internet attack, we see many more internal attacks within larger organisations which involve rogue server or services being established within the firewalled trusted network. As a result, this lifts the threat level of internal systems/services and therefore the need for effective timely patching.

Also consider asking the question of your hosting facility, upstream ISP or DNS provider to see if they have patched their DNS servers and forwarders.

http://www.doxpara.com/?p=1162 This link also has a DNS checker.
http://afp.google.com/article/ALeqM5hwFqcnWAuDWlcqfvfyHu5PGG9RMQ
http://www.kb.cert.org/vuls/id/800113

This is a full list of vendor patch links
http://www.betanews.com/article/Major_fix_to_DNS_vulnerability_impacts_Windows_Debian/1215551008

Good Luck