This is the most comprehensive all-time Bitcoin price history chart you will find online. Updated daily. The chart is interactive:

On 2009-10-05 the market price of Bitcoin is first established at $0.000764/BTC by New Liberty Standard, the first Bitcoin exchange ($1.00 buys 1309.03 BTC.) The exchange rate history is available at two archived pages: first, second. Their last known exchange rate is $0.005472/BTC on 2010-03-02.

On 2010-04-25 the market price is established again at $0.003/BTC, using the daily volume-weighted trading price of the second Bitcoin exchange, BitcoinMarket.com (PayPal USD trades). The owner, dwdollar, actually started operating it on 2010-03-17, however trading data for the first few weeks is—to my knowledge—not available.

After 2010-07-18 the Bitcoin exchange rate is from the CoinDesk BPI.