IF YOU USE a wireless connection between your iPod and your car radio speakers, you might want to avoid an upgrade to iTunes 7 becacuse the upgrade normally wipes the radio station menu from your iPod, as Security Monkey reports.
We faced that same problem several versions of iTunes ago, which is why we don't upgrade iTunes anymore. Actually, we listen to our podcasts in our car using our Sony Walkman phone through the car's speakers, without using a hands-free kit.
Security Monkey -- "Latest iPod Upgrade Breaks iPod Car Interfaces"
Bonus Link: Walkman Phone Podcast [25.7 MB 96 kbps MP3 file]