i dont think there is an app that does this. and its a great opportunity for developers. i dont know why there isnt an app that you can enter you monthly minutes and text and data amounts, and it keeps track daily. and when you approach the limit, it gives you a warning. that would be simply a brilliant app.
I'd love to have an application that does that, the phone has a log for calls however not one for texts.
If you're lucky you can find out through your network service provider if you have an online account because they keep track of your allowance and used texts/ minutes. However there is usually a note indicating that minutes and texts may take 2 days to appear.