For iPads running iOS v5.1 or later, a free iPad version of the ATOMDB database browser is available from Apple's app store.
View emission lines in a graphical display, or a tabular format as shown here:
View strong emission lines organized by temperature group, here in graphical format:
Or select ions and view specfic level transitions in detail:
See the downloads page to download the Objective C source code for the iPad application.