Originally Posted by Bobbles
I loved c25k when I did it... never thought I could run more than 1/5 of a mile, and that would've been on a good day!
The only difference i noticed between training for the 5K and actually running a 5K was that I was SO used to the feel and constant speed of a treadmill that the feeling of running on asphalt came as a rude shock... I felt sluggish and my legs hurt, so you may want to consider possibly throwing in some training outdoors to prepare yourself for it.
I agree that a lot of the running should be outside. Its quite different as you are needing to propel yourself forward, not just lift your legs up and down while the treadmill belt moves. Also, I found the beginning stages of C25K frustrating on a treadmill, since every couple of minutes you are hitting the "increase speed" and "decrease speed" buttons. I also found it easier to regulate my speed outside, since I could speed up or slow down as needed, without hitting buttons.