Same here. I only watch live on afternoon and night races, and I DVR all the morning races and watch those as soon as I got up. The iPhone app is uber cool during live races.
I found an app called “Keyguard Disabler” which might do what you want, but it cost $1.49.
If you like using the iTune infrastructure and do buy music with it, then get the iPhone. However, able to run multiple apps at the same time is very useful, not to mention once you have the internet in your palm, you will be surfing the net and not listen to music…:rofl