yahoo options site (http://finance.yahoo.com/q/op?s=GOOG&m=2010-07) show they expire at close Thursday, July 22, 2010 ? while CBOE says they all expire at Friday. (http://www.cboe.com/micro/weeklys/introduction.aspx)
Yahoo listing looks like an error, my app shows 3 days till expiration meaning they expire on market close Friday. Generally speaking options data on yahoo finance is unreliable IMO.