This is something I've been talking about for a long time in these forums (and been accused by some of being a "communist apologist" for doing so); China's leadership is not a homogeneous group of leaders who all support the gov't's oppressive policies. There are quite a few reformers, also.
Wen Jiabao is one of those...while he publicly hasn't said much until recently, behind the scenes he's been quietly working to put other moderates/reformers into positions of power. But now he seems to be taking a much bolder step, publicly calling for significant reform within the party. This includes calls for greater freedom of speech, and for greater political transparency.
A number of key party officials have spoken up in support of him; and using the fact that his comments have been censored from the Chinese media as a sterling example of the kind of thing that should not be allowed in China.
I think that the timing is somewhat tangentially related to the Nobel prize being awarded to Liu Xiaobo. Not that any of these people are speaking up in favor of Liu, but rather that the major national awareness of freedom of speech issues that's arisen as a result makes the timing of Wen's comments quite strategic. All of these people are being careful to distance themselves from Liu ("He seeks change from outside the gov't, causing disruption and disorder; we seek internal change that has positive results without disrupting society"); but for all that, their goals are actually very similar.
There are, of course, factions within the Chinese gov't who are very resistant to such ideas; but whispers are that within the next week, a slightly amended version of Wen Jiabao's comments (and those of other senior party leaders) will be released in the official Chinese media.
Is gonna' be very interesting to see where all this leads.