The one on the n93 works fine, though it's useless for 99% of people. All a barcode is, keep in mind, is a series of numbers with a certain font applied to change it to look like a barcode. For example, on postal bulk mail, it's called a 'postnet barcode', and looks like this: :39939399393:
Anyway, the n93 app just translates it into numbers.
-olly