You could do it a few different ways, but the easiest is where you display all-time minutes on your Message Board posts. Here's how to do that: www.sparkpeople.com/community/help_answer.
If you don't want to keep that info on your posts, you could always turn it on, get your number, and then turn it back off.
Hope that helps,
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford