OP, do not be deceived by the word 'shortcuts'. In iOS 5, shortcuts is your dictionary. In order to add a word to the dictionary, just go to:
Settings > General > Keyboard > Shortcuts
Then type the desired word into the 'Phrase' field, but skip the 'Shortcut' field. Click save. Voilà!
Now the word is in the dictionary and it will never prompt you to correct it.