Great post by The Sorcerer.
As he said, a lot of people write reviews without seeing the product. There may be nothing wrong in it as long you do not claim otherwise. I have written a lot of such reviews but eventually I managed to get hold of companies and started receiving products for review. In my humbleopinion, you must first prove your ability to write great reviews and your blogs should have good visibility before companies start giving you products to review.
Attend all blogger events, PR briefing and product launch events in your city. That will give you contacts with companies which will eventually help you getting products to review.