Most meters should also have the option to do this for you - have a look in the manual for yours, as you may need to set this up.
I have a Contour Next and it can record the last 800 readings split into fasting, pre and post meal, and non specified categories, and will show averages for each over 7,14, 30 and 90 days, plus more.... All the data can be uploaded to Bayer's free software on my PC which will give further statistics.
I have an iPhone and there's an app called health (white icon with red heart) that allows you to input your readings and shows a graphic representation of them. It just appeared in an update a couple a while ago. I didn't download it. It also allows you to use your phone as a pedometer which is very handy.
If you're tracking everything mysugr logbook is probably the one I'd use.
If your 100% gonna use your phone I use the my Dario app/tester (mostly because it's the most compact tester you can buy...)