If your overall transaction number is low and you will be running it only once a day like you stated, DTS may be the way to go. We do something similar, and it works fine. You can query on dates so that you only get the updated/new records. You can use the Microsoft ODBC Driver for Oracle if you don't want to install any Oracle components on the SQL Server box.

If you're going to do something more complicated than that, you may want to look into a more sophisticated tool, but why spend the money purchasing and the time and effort building something else if you can utilize something you already have in-house.

Also, I've heard that improvements were made to DTS in SQL Server 2000 vs. 7.0.

Good luck!