Although the Belkin site says that the Auto Kit for iPod with Dock Connector is "Coming Soon!", I can assure you that both the local Tysons Corner Apple Store and Apple's online store have the product in stock. Why is this of interest? Because, it contains not only a jack for power through your car lighter, but also a 3.5mm line out jack.
There are also a bunch of new accessories in stock or coming soon for the new iPod's with dock connector.
The bad news is that the old 'pod's won't work with them, at least most of them. However, the good news is that the new ones will have a ton of options for people looking to accessorize.
Also coming soon is the Belkin Battery pack for iPod - uses 4 AA batteries to get on-demand additional battery life (12-15 hours).