do you intend to use it during preparation for the debate or at the debate itself, and how exactly do you intend to do it?
1. for reading pdfs, i recommend goodreader.
2. for flashcard training (will you need it?), i recommend gflashpro.
3. for notes, i recommend evernote.
4. for recording (yourself or others), i recommend recorderpro.
5. for organization, i recommend voodoopad.
6. for speeches (perhaps not appropriate for your competition), you might want to try onair (teleprompter). i haven't used it, but i used something similar at my last presentation.