The Murdoch PAC is called News America Holdings. Like most industry PACs, they spread their money around. Last year, according to Andrew Belonsky, the Democratic Senatorial Campaign Committee got $15,000 and the Republican committee got $20,000. Amusingly, Harry Reid got $5,500 from News Corp in 2008 and his campaign got another $3,500 this quarter.
Every major media company has a PAC, and all of them donate to politicians in both parties—because neither Democrats nor Republicans are enemies of media conglomerates. In fact, the Clinton years and the Telecommuncations Act showed Democrats could be very friendly to media conglomerates. They'll neuter the FCC's regulatory authority, and unlike the Republicans you don't have to worry about a puritanical crusade against indecency! (At least since the Gore/Lieberman ticket didn't actually succeed in taking office—their FCC chairman might've been worse than Michael Powell.)
Now Rupert himself is, obviously, the driving force behind the PAC, in terms of where they get money and where they send it. He donated $10,000 last year. Most of the rest of the PAC's money came from small donations. These were probably Fox employees who were strongly encouraged to send in couple hundred bucks, regardless of whether the PAC represents their own political beliefs. (It represents no political belief besides Making Money for News Corp, obviously, which Republicans and Democrats are both fairly friendly to.)
Take Peter Chernin. Chernin was News Corp's President and COO from Cotober of 1996 until last year. He donates exclusively to Democrats. Al Franken, Barack Obama, Christopher Dodd, etc. etc. Big Hillary supporter. Plus: $5,000 to News America Holdings in 2007!
Chernin was replaced by Chase Carey, the former DirecTV CEO. Carey does not donate much. But he gave Tom Daschle $1,000 in 1998. And then, suddenly, a couple months after returning to News Corp, boom: $5,000 for News America Holdings from Chase!
Roger Ailes has not contributed to the PAC, by the way, since 1997, when he mailed in $5,000. So: maybe he is going rogue! And it's funny that News Corp's "liberals" are less likely to stand by their principles than the guy who's driving the company even further to the right than Murdoch is comfortable with.
So basically a media company whose most profitable arm is a communications division of the Republican party (and a fairly successful entertainment company) also runs a legal political bribery organization that buys off politicians from both parties, and all the liberal employees of this conservative media company have to contribute. Also almost none of this is out of the ordinary.