In the built-in character sheet, a double weapon is shown as getting an extra 1/2 STR bonus for being wielded with both hands (as opposed to double). However, on the Paizo forums, James Jacobs ruled Nov 9, 2009, 12:56 PM this is incorrect ("while you wield a double weapon two-handed... the rules treat it as if you were wielding two weapons one-handed").
This issue is also summarized in Quandary's FAQ candidate post dated Jun 7, 2011, 10:27 AM.
This issue is also summarized in Quandary's FAQ candidate post dated Jun 7, 2011, 10:27 AM.