Facebook says that at this point it will not take down a Wikileaks page on its site. The fan page has nearly a million followers/friends/likers/whatever and Facebook says, "The WikiLeaks Facebook Page does not violate our content standards nor have we encountered any material posted on the page that violates our policies." It's a carefully worded statement that leaves open the possibility for encountering something that does violate those policies, of course. But Facebook tends to be pretty open about groups, refusing to take down a Holocaust denier group, for instance, citing free speech.
Meanwhile, Visa is suspending payments made to Wikileaks after Julian Assange was arrested in England on sexual assault charges.