Sergio describes on his blog how you can connect with sql+ to to a database without the need of the tnsnames.ora file. This is great, but only available since 10gR1, and you have to provide the password in the connect string.
Aino Andriessen is a consultant on Enterprise Java, ADF, PL/SQL, XML, and SOA development and is Expertise Lead on Application Lifecycle Management (ALM). He has a strong interest in ADF, SOA, Maven, architecture, quality management, delivery and application lifecycle management. Aino publishes on the AMIS technology blog and has been a presenter at the ODTUG Kaleidoscope, Oracle Open World and UKOUG TechEbs.