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Generally a good listing in DMOZ (Open Directory Project ODP) is one of the better things happening to a website :)
All major search engines spider the ODP and being listed there is a perfect way to get into search indexes worldwide.
A listing in the ODP also tends to give a site a boost in ranking in most angines, since it's considered being a valuable link.
To change an existibg listing in ODP there is a routine. In the german section of the ODP you navigate to the category the listing sits in, then at the top you chose: "URL aktualisieren".
Hope this helps. Else just keep on asking. We have some very knowledgable ODP specialists here.