Check the oracle magazine on otn.oracle.com/oramag
In the peer-to-peer, you can read more about 3 Oracle Aces, Steve Karam, Nicolas Gasparotto, Dave Moore.
In the technology columns, three more aces talk about Oracle technlogies. Steven Feuerstein about The Right Place for PL/SQL, Arup Nanda about Recover in a Flash, and Tom Kyte about On Top-n and Pagination Queries. Tom also remind us that group by does not sort. However, if you have one application which used to expect sorted result in 9i and is now produced unexpected result in 10g, you can still read the Note:345048.1 in Metalink to find some workarounds, for example by deactivating hash-group-by with _gby_hash_aggregation_enabled parameter set to false