FamilySearch Indexing is a free app for smartphones and tablets (Apple iOS and Android). Using this new app, you can transcribe names and upload them to FamilySearch for submission. Note: See update below.
The app changes the way indexing is traditionally done. Instead of committing 30 minutes or more at a computer, mobile users can do one name at a time, taking advantage of small bits of time you may have.
Update March 11, 2014: The beta (preliminary) test of the FamilySearch indexing mobile app has been completed and the app has been removed from the app stores for further downloading. No new images are being published for the mobile app so those who have downloaded it should discontinue using it. A new web-based indexing program is currently being developed for both desktop and tablet computers. For more information, see The Future of Indexing. Meanwhile, you can visit FamilySearch.org/indexing to download the current indexing program.