Downloaded the newest official XCode tools. The new tools include iPad support. I tend to avoid beta releases of developer tools.
Seems real easy to convert the app to a universal app -- an app that runs on iPod/iPhone/iPad. Basically, control click on your target and then update it for iPad. XCode creates a different xib file for each device and changes project settings automatically. It does give an option to create separate binaries. Now you can create completely different layouts with interface builder for each device which is sort of cool. The app must run on os 3.0 or greater.
There are some info plist settings that need to be added. For instance, supported interface orientations. All orientations need to be supported on iPad and I'll have to review that. There are different icons that can be added beyond the typical 57x57 icon on the iPad. After converting my latest app I've been working on to universal, I created one of the default applications that XCode creates and compared it.
Some minor things I've run into are assuming the height and width of the viewport can be a problem. Its different dimensions on the iPad. Also, there is much more real estate for the cocoa touch interface that presents the game. Lots of space to use. Icon sizes can be a problem too -- too big or small.