I've been using Dynmark for some time, which I would recommend, but their texts used to cost as little as 5p. Unless you buy a massive amount, you're looking at around the 7p mark, now. Definately easier than messing about with a phone keypad, though!
I can recommend that Dynmark if you ever fancy it. You may get a few free 'uns if you sign up? However, my original post.....is it not possible to email direct to a mobile? Or possible but not allowed.......!