Google Now Supports NOODP META Tag
According to Matt Cutts google have added support for the NOODP META Tag.
In some circumstances Google have used a websites description taken from the ODP (dmoz) entry as the description in the SERPS, This has confused and sometime angered webmasters. The thing is, The internet and our websites are fluid and ever changing, Something which the ODP is not. By adding the NOODP META Tag you can now instruct Google to not use the dmoz description in SERPS.
At present the only major engines supporting the NOODP META Tag are MSN and Google. Yahoo use the description from their own directory in their SERPS, So it is unlikely that they will implement the NOODP META Tag, Or bring out a meta tag that allows webmaster to stop them using the description found in the yahoo directory.
If you want to add the NOODP META Tag to your site to prevent Google using your dmoz description in SERPS add the following code to the head of your page
<meta name="robots" content="NOODP">
Of course, You wont need to do this if your site isn't listed in dmoz and you wont have to do it if google don't currently use your dmoz description, But there is no harm in adding it anyway.
Matt Cutts recently added this to his blog as a bit of an experiment and he found that it took effect 3 to 4 days after his page was crawled.