Brick By Brick is an Apple iOS app that is optimised for iPhones but will also work on an iPad. From the description in the AppStore:
Browse and search Brickset database:
- browse by themes (sub themes or year) - search option available for sets.
-user can add to want list and change number of owned, edit set notes, visit Brickset site and share Brickset
url on Facebook and Twitter.
-for sets with instructions, user can download instructions and they are later available for viewing so the user doesn't have to re-download them each time.
-pdf viewer for instructions with bookmarks and printing options.
-set picture can be enlarged, and sent to email or saved in database.
myBrickset is the first Android app for Brickset. It has been developed by forum member RikTheVeggie. The Google Play description reads:
Browse the LEGO catalogue & prices offline. Sync your wanted sets with Brickset.
Browse the entire LEGO database offline, including retired sets. Includes retail price information for the UK, US and Canada - never wonder again if you're paying too much for your LEGO!
Powered by brickset.com - the friendliest and most comprehensive LEGO fan site on the Internet.
Seamlessly integrates with brickset.com to keep track of your owned & wanted sets.
Automatically updates with new releases, pictures and price information as it becomes available.
This is an excellent app that works well if you're without a data connection but if you have one available it provides a complete Brickset experience including access to the large set images and also instructions at LEGO.com.
Both of the apps are free so if you have an iPhone or Android device I encourage you to download one and give it a go