Should be able to see that from the Carrier site, your account info. I know I saw it once on my ATT account, unless that is changed. - I assume the same for Sprint......
Just log into what your acount. Then u will be able to see ur usage of text messages. I do not worry about that, I have unlimted texting. I am a newbie. All I have to say is Blackberries rock!!!
With sprint dial *2 and it gives you an option to verify the mins used and the # of texts used on your billing cycle for +- 10 mins from the moment you called.
Posted from my CrackBerry at wapforums.crackberry.com