Eclipse/Oracle Problems

Can someone give me a detailed walkthrough or point me to good resource on how to connect to an oracle database from eclipse? I have downloaded oracle/sql developer/and moved ojdbc6.jar under my library. However, when I currently try to run .JSPs I connecitng to a database I get the following error:

"javax.servlet.jsp.JspException: Unable to get connection, DataSource invalid: "java.sql.SQLException: IO Error: The Network Adapter could not establish the connection".

Any help would be very appreciated.