i do not have alot of experience with oracle, but i've been dealing with insert issues in other databases lately. here's some things you can try:

• see if oracle comes with a tool that will import csv/tab-sep data. this is often many times faster that putting it into sql and inserting it.
• check if oracle supports multi-insert syntax, where you can specify more than one records' worth of data per statement. this will greatly speed up your queries.
• turn autocommit off. this is an easy one. you may also have to wrap the inserts in a transaction.
• disable indexes/keys if oracle supports it. then enable them at the end of the script.