Oh my gosh!
I LOVE RUNNING!! !
I have been in cross-country all throughout high school, and I ran track up until this year (now I am training for a marathon).
I used to run a 12:30/13:00 mile....then I went to the gym for 3 days (not next to each other) and ran for 5 hours straight (with 10 min. breaks when I "felt it") and my time went down to a 9/10 min. mile.
Weird story, point is, now I can run in the 6's (PR, 6:08, recently: 6:17) and once you break the 10/9/8 min/mile break.....you can do pretty much anything!
There are 2 types of running (personally, I think the long runs are more rewarding)
and the type that Nosirrom was talking about is great for general health but if you want to lose weight and stuff, you have to do faster on the runs you can already do.
Oh, and if you EVER have any questions about running, don't hesitate to pm me, running is my passion and I love helping people with it and stuff.
Have good luck with running!