nxtBlock is available for iOS (iPhone/iPod Touch/iPad)
nxtBlock Server, which is needed to transfer the program to your NXT, is available for Windows & Mac OS X.


nxtBlock is available for download in the App Store.

nxtBlock Server (Windows):

Download Link (Windows XP)
Installation instructions for nxtBlock Server on Windows can be found here.
Note: You will also need these drivers:
Bonjour Print Services
- Lego's Fantom Driver

Important! For nxtBlock Server to run on Windows 7, compatibility mode needs to be set to Windows XP (Service Pack 3)

nxtBlock Server (Mac OS X):

NOTE: Rossetta must be installed for nxtBlock Server to work. (How to install)
nxtBlock Server for Mac OS X is available for download here (Mac App Store availability coming soon!). 
Installation instructions for nxtBlock Server on Mac OS X can be found here.

If you are looking for sample programs for nxtBlock, they can be found here.