Been looking around in itunes for a sms app which can tell me how many characters ive keyed in so i can i tell if i am sending one or two sms but there's so many sms apps and i m not sure which one can do this

Hence, i m asking if anyone here can recommend me a sms app which does what i just mentioned and it would be good if it's free. Something simple. Just for me to keep track of the length of my sms before i send it out.

Thanks!