I've been playing for almost 20 years, and I still can't play!! j/k
I taught while I was in High school for some extra money, so here come the pointers....
First of all, make sure that you get a good quality guitar. Some students are so disappointed in their guitars that it adversly (sp) affects their learning to play. You can pick up a good quality acoustic guitar with none of the bells and whistles for well under $300, and better deals can be found everywhere.
No matter how disappointed you become, stick with it. A whole lot of people give up right off of the bat because they aren't seeing the results that they thought they would see, but they don't realize that the next plateau of ability is only a few days away and that they will be amazed at what they can do in a relatively short amount of time it they
stick with it.
Make sure to buy quality training aids if you are not going to get a teacher. (I am self-taught, and therefore proof that it can be done.) I used to use the Ernie Ball books to teach because they provide a good foundation in both music reading and chording. My advice is to ask around a music store and pick up some training aids based on your musical preference and the advice of the people that you talk to. Any music store should be glad to help; after all, you are future business!
Lastly, and I hate to say this, but practice really does make perfect. (I could fill this paragraph with more cliche's, but I won't

) When I first started playing, I would play until my fingers bled...and then I would play some more. (I'm not kidding, either!) That's the reason that I can play as well as I can. Every other guitar player probably has a similar story.
Sorry that this went on for so long, but when I get to talking about music, I just can't stop. Feel free to PM me if you have any more questions!
Ribb