After Brett Favre's dad, "Big Irv," died last month, even Eagles fans felt sorry for the Green Bay Packers' star quarterback.For about three minutes.Then we found out the Birds would be playing the Packers in the second round of the NFC playoffs.And now, Birds fans are bad-mouthing Favre, big time.On talk radio, they mocked his dad's ascension to heaven.On the Internet, they're laughing at the idea that, as one TV sportscaster proclaimed, "There's an angel on the shoulders of the Packers."The trash talk at the Eagles' official fan site only ceased when the Web site moderator threatened to ban anyone...