Homescreen++ is a Today Screen add on for 6.1 that does this. I use it. It will keep track of incoming, outgoing, and show both together and you can set it to reset on a certain date. It also keeps track of data usage and will reset that too on the date set. It can display this info on the today screen along with other info such as memory, cpu activity, and other info. You can get it at
www.chi-tai.info