Macworld: iTunes 3.0.1: "Navigate to the folder that contains the tunes on the networked volume and click the Choose button in the Add to Library window."
Some good tips. A few others:
1. iPod only displays the first few characters of song titles, so make them meaningful (esp. for classical and opera).
2. Use the custom genre unless you want Opera treated as classical.
3. The Genre hierarchy is: Genre:ARTIST:ALBUM:Song. Not very useful for classical music or opera where the COMPOSER is of primary interest. So consider #4. When classical music spans CDs, consider giving all the CDs the same album name.
4. Consider creating a smart playlist by composer for classical music and opera only rather than enabling "composer" in the top iPod menu (it's disabled by default).