I'd say that you need to figure out what you're expecting to do, long term, with the guitar. If you're just looking to strum chords out, it doesn't really matter who teaches you what and you can certainly teach yourself. If you're wanting to extend that to play riffs and some lead GET A LESSON, even if it's only one. There are fundamental building blocks that you need to know and once you've developed your bad habits, they're hard to break.

Example:
I started playing about two months ago. I play about 2 hours a night every night... more on the weekends. I had my guitar for a month before I had my first lesson and the fundamental things that I was doing wrong would have hindered me the rest of my guitar playing life (playing the G chord with the wrong fingers, holding the pick wrong, holding the guitar wrong, resting my arm on my leg, etc). Sure I would have been able to strum out around the campfire but I would have only needed the first three frets.

Sorry for the long post, but hopefully it'll help.