Is there a car-friendly way to play music on the iPhone without a car kit? I'm wondering if there is a car-friendly way to play music on the iPhone without any type of car kit.  Specifically, I am looking for a way to change tracks without unlocking the phone.  I'm okay with pressing the home button, I just don't want to worry about unlocking the phone.  

Some examples would be:
1) Swipe controls accessible from the lockscreen.
2) Shaking/moving the iPhone in a certain way.  

I know Siri can do this, but I was hoping there was a way to accomplish this pre-Siri.  

The normal music player on the lockscreen is not suitable for driving, as I have to look at the phone to press the touchscreen in the right place.
You could get something like this remote, which has passthrough for any standard 3.5mm audio, and provides volume controls and a clicker remote (just like on Apple's headphones). The clicker can to play, pause, and skip (double click for forward, triple click for backward).

There are other similar products out there, I found a few by searching for "iPhone inline remote".