update 8pm: Exclusive with the Incumbent. Nuraina A. Samad, former political editor of NST, had lunch with Rafidah Aziz, it would seem from her posting Rafidah will defend her post.Rafidah Aziz, the incumbent president, told some friends over lunch today that "if that's what Shahrizat wants, I'll see her in the ring in March."
20/11 Wanita Umno deputy chief Shahrizat Abdul Jalil has announced she will be contesting the chief post/STAR
You can see this in any which way but, in essence, Shahrizat has broken an August 4 pact between the two, endorsed by the movement, for a peaceful and smooth hand over in June 2009.
Nuraina had predicted that Sharizat would take on Rafidah, here. Sakmongkol's analysis here is spot on, too.