If we're being serious, I'd think that's too much, as you need to look at the screen to do that.
I find it quite interesting though, my phone is my satnav. So by the letter of the law, I can legally program that whilst driving but not use it as a phone. Even though it amounts to doing the same thing.
( the mighty badger Aphrodite, on a bar stool, by your side, Tue 16 Jun 2009, 13:17, archived)