I would avoid the 30 day thing. It's just not possible to learn the guitar in 30 days. There are endless websites available for free that can help. If you want to spend a little money, look into getting Guitar Pro 4. It's a great learning tool. Check out this site, it's where you can download songs of all styles to use with guitar pro 4....

http://www.mysongbook.com/

The great thing about it is that you can slow down the tempo of the songs without changing the pitch, so you can learn them slow, then speed them up when you feel comfortable. This will help with your rhythm playing.