10g data dictionary docs?

in 8 and 9, oracle had the link to the data dicionary docs right on the main page. They reorganized it with 10g and I have been unable to find them. Instead of a link can someone tell me how to navigate to it from the main page(getting started) When I do a search all I get are links to the concepts and the reference guide. There used to be a doc that explained every column. Thanks

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http://www.freelists.org/webpage/oracle-l