Use this simple, self-contained class definition to obtain quotes and historical data from Yahoo finance.
f = stock('f','5y','d);

creates a stock object with a current quote and five year history of daily data for the stock symbol 'f' (Ford Motor Company).

f.plot;

charts the historical data. The default disp(f) method returns current quote information.

disp(f);

Ford Motor Compan (NYSE:F)
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Last Trade: 16.28 (4:01pm 11/19/2010)
Daily Change: 0.16 (0.99%)
Prev. Close: 16.12
Day Open: 16.02
Day Range: 15.83 - 16.38
52wk Range: 8.40 - 17.42
P/E 8.53
Dividend Yield N/A

Daily Price History: 21-Nov-2005 to 19-Nov-2010
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Volatility: 60.40% (annualized)
Mean Log Return: 14.09% (annualized)

Additional properties and methods provide access to wide range of data for the selected stock. The individual objects may be stored in structure arrays to track investment portfolios.