The current installation procedure for Oracle requires the Oracle SQL files to be copied over the PostgreSQL versions; this is a kludgy modification to the source code hierarchy that renders your local copy different from the prototype, e.g. in svn. This is an unnecessary and gratuitous difference, and it also adds a confusing step to the installation just for Oracle users, who are already likely to be more confused than their luckier PostgreSQL colleagues.
I propose putting the SQL files for Oracle, PostgreSQL, and whatever other DBs may someday get supported, side-by-side in peer directories, and have them used in place without any copying. The only change to the source tree would be to add dspace/etc/postgres and move all the "default" SQL files in dspace/etc to there. Then, the build.xml script would simply insert the value of the "db.name" configuration property (ant can read properties easily) into the path, or modify org.dspace.storage.rdbms.InitializeDatabase to do so. There would no longer be any need to modify the source tree as part of an Oracle installation.
I'm willing to do this and update the documentation, for 1.6.