Elder of Ziyon yesterday ran a story according to which Arabs can immigrate without impediment between Arab states... unless they're Palestinians. Palestinians are not allowed to be naturalized in other Arab states, according to a policy agreed upon by the Arab League “to avoid dissolution of their identity and protect their right to return to their homeland.” (says this fellow).
Elder speculates that large numbers of Palestinians would move if only they could; I'm more interested in the hypocrisy. Think of all the people in the West and in the Arab world who castigate Israel for impeding Palestinian immigration (mostly since 2003), while somehow overlooking the fact that they're not allowed into most of the Arab world, either.
If anyone has additional information about the matter, feel free to enlighten us in the comments.