This is the first step in your aviation training. Lets go over the requirements and the approximate costs.

FAA requirements:

Age - 17+ years old
Education requirements - Able to read, write, and speak English fluently.
Flying time requirement - Minimum of 40 hours of flight training. This must include: Conversely, if you fly twice a week, it will probably take fewer total hours to get your license. This training must include a minimum of:

20 hours of dual instruction including:
3 hours of cross-country to airports more than 50 miles away
3 hours of instruments
3 hours of night including a 100 nautical mile round trip and 10 night takeoffs and landings
3 hours of instruction within 60 days prior to your practical test

10 hours of solo flight including:
5 hours of cross-country including a 150 nautical mile round trip
3 takeoffs and landing at an airfield with a control tower

Examinations:

1. Private pilot knowledge test with a score of 70% or better. There are 60 multiple choice questions.

2. Practical flight test with an FAA-designated examiner. Nationwide, the pass rate is about 90% for students on their first try! The exam contents is defined by the FAA's Practical Test Standard (PTS), and it includes both an oral exam and a flight test.

Average time to get private pilot license in US: 55
Approximate Costs - $6000 - $10000
Recommended way to train: Fly 2 hrs / week in the start. This is the optimal way of training to get your license in a cost and time effective way.

Reference:
1. Look at FAA's databank of about 700 questions for examination questions.
2. Check out Private Pilot License related books