An iPhone with a Keyboard?

So sometimes while on the road i find myself typing long drawn out emails from my iPhone's touch screen and its becoming increasingly easy, as well as annoying....Im interested to know if anyone uses a keyboard with their iPhones.I dont need a full sized keyboard, all though it would be nice, but im not trying to add pounds to my day bag, but maybe a few ounces. I have come across this qwerty slider case option but it adds a bit of bulk and i havent heard or seen really anything positive on them. One of my co-workers has put me on to this Freedom Input mini keyboard and it looks like what i need. Small compact and bluetooth...anyone have any input on a device like this?