Most of the larger A/V firms (Symantec, McAfee, Trend, Kaspersky...etc) already have signatures in place to catch/block the malicious files.

A contributor of Securiteam's website wrote the following as an interesting layered approach to prevent infection via applying a Software Restriction Policy:

Windows XP users have a little-used weapon that they can use to blunt the effect of the in-the-wild malicious code targeting this vulnerability: software restriction policies. By using the “Basic User” SRP, users can launch Microsoft Word without the ability to write to certain registry and file system locations that the in-the-wild malware requires access to. This is a stop-gap measure based on the threat profile of the in-the-wild malware at this time and is only necessary if you’re still running interactively as an administrator. If you are, it should be a priority to change that if at all possible.

I’ve produced a simple registry script that sets a Software Restriction Policy that runs any instance of ‘winword.exe’ with the ‘Basic User’ policy. Once the registry script has been imported, the SRP can be rolled back (if desired) via the Security Policy snap-in.
The full article can be found here

He also offers a link to the registry script that will modify the Security Policy.

*just an update, might as well share some of this info with the rest of you*
If you are running any of the following hardware firewalls that include A/V services, you should be protected: Checkpoint, Fortinet, CiscoASA, Aladdin Esafe

Couldn't get ahold of anyone at Watchguard or Sonicwall to find out if their A/V sigs protect against this vuln or not and their site did not provide anything useful....especially sonicwalls - last virus update notification was oct 05 *winces*