One of my favorites, Distant Suns [App Store] has updated the build that runs on the 3GS iPhone to include some augmented reality features. This means that if you point the phone up to the sky, the program figures out the direction you are pointing and your elevation and slews to the proper view of the star map, giving you a view that should match what you are seeing in the sky.
This greatly enhances the usefulness of this program, especially for novices who want to get outside under the summer stars and quickly figure out 'what's up?'.
This new version is only for 3GS iPhones, and an update with some additional features for all the earlier models is on the way. Of course older phones won't have the compass feature. Other changes include some UI tweaks, and setting the sound effects default to 'off.'
Pocket Universe [App Store], which I reviewed last month, has a similar feature and also works very well. Pocket Universe sells for US$2.99 and Distant Suns is $5.99. Check reader reactions to both and go into details on the features to decide which one is right for you.
Distant Suns has a long pedigree in the star mapping world. It first ran on the Commodore Amiga in 1987, then was ported to the PC, the Mac, and now your favorite cell phone.
When you look up at the moon this summer to celebrate the Apollo 11 landing 40 years ago, be sure to investigate the thousands of other points of light with a software app that will literally point you in the right direction.
Note: Distant Suns runs on the iPod touch as well, but the software will not have the augmentation/orientation feature because the magnetometer isn't present in the iPod touch hardware.