iPad launches in the US next Saturday, and all the iPhone developers out there have by now submitted their applications to be considered for the App Store on launch day. I, like Marco Arment, don't believe I will be running any iPhone apps as-is on iPad, and ergo don't believe you should have to either1:
"But then I saw the pixel-doubled version of my app in the simulator. It sucked, and it was completely unusable by my standards. I don’t think I’ll want to run any pixel-doubled apps on my iPad in practice."
With that in mind, I have submitted Universal updates for Grace, Speed and SameGame which will hopefully be live on launch day so that you have a fully iPad-compatible version at no extra charge when you get your iPad. As-is, they all have pretty much 1:1 feature parity with the iPhone versions. I'm working on some very cool updates to make use of iPad-specific features and UI, but they'll be gestating a little while longer.
The great thing about iPad's increase in screen size is that you can design brand new experiences into your apps that were never feasible before, for example two-player on-device multiplayer, and proper car dashboard replacements, etc. I'm really excited about what I'll be able to produce in the coming months.
1. One app you'll notice missing from my initial lineup is Lights Off. To be honest, I'm still figuring out how I can bring Lights Off to the big screen without it sucking, but I'll make sure to keep you up to date. It's something I want to bring to iPad fairly quickly. Also at this time I have no plans to bring Nuker to iPad; it's a more widgety type application and I don't think it would bring anything to the table on iPad.