I use
http://www.sharpbettracker.com/ to keep track of my win/loss numbers and profit/loss numbers (I assume that's what you meant by P and L?).
Plus, it breaks down my bets even further, showing me how I did on different sized bets or on different types of bets (runlines vs moneylines vs totals for example). I find that super helpful so I can find out where I'm strongest and where I'm weakest.
The entire interface is super easy to use too, which is an added bonus, especially since I can access the site from my iphone and have my stats available to me whenever I want.