Today an open letter was posted to the interop site at Microsoft. Yesterday, an open letter was posted from Sun, which I commented on in a blog post yesterday. IBM delivered a new product suite to market in the same market segment. Things are getting interesting.
As for the IBM product - I'd like to reiterate how much the release of the new product offering factors into their stance on Open XML. As for the product they are selling, there are some skeptics as to the value of their offering - read this from Forbes Magazine.
Coverage on the open letter: Galli at eWeek, LaMonica at CNET and ZDnet. I'm sure there will be more.