The GSDList app is available for iPhone and iPad on the App store:
GSDList App Download
What's new: multiple locations possible for each keyword (you can have as many locations named "Grocery" as you want); "More..." button in new item screen to enter more detail, tags, etc; performance improvements and bug fixes.
GSDlist™ is a new way to manage ToDo lists.
If you installed the beta iPhone app by sending us your UDID in the past, you should delete that app from your phone and download the released version from the App Store (see link above)
The main interface for GSDList is on this web site. The mobile app is a subset of the functionality of the web site -- the part you need on the road: