Oracle Locator and Spatial
If you already use Oracle Spatial or Locator then you probably already know Simon Greeners SpatialDB Advisor blog, but if not then I can recommend it as an invaluable source of Spatial nuggets. Whether you are just starting out with Spatial or have some level of experience with it you will find something there which will knock your socks off! When I was helping a client with creating a geo-spatial database I found it confusing with regard to what is included as part of the Locator licence ('free' with Enterprise Edition) instead of the additional fee option of Spatial. One of Simons posts really makes it clear what is and isn't included with Locator, and thus I was able to ascertain that the client only really needed the functionality available within Locator, resulting in a considerable saving on licence fees for the Spatial extension.