The Premiere Pro 3.1 update has been posted on the Abobe site for Windows & Mac. This update adds Panasonic P2 MXF compatibility plus a few bug fixes. Note that P2 MXF support in AE is not included.
The update has been available via the Adobe Update Manager, which hasn't been showing updates for some people who used the public beta. Details on the release were posted here previously in AE & PremierePro's P2 support, 3.1 upgrade available.
Update: The EditBlog discusses Editing P2 media on Avid.
Update 2: Adobe has a Premiere Pro Update for Intel SSE4.1 on Adobe Labs, "In November 2007, Intel released the Penryn family of processors that support new instructions called SSE4.1. These processors are identified by the 45nm production technology and one example is the Intel Core2 Extreme Processor QX9650. These new instructions are very helpful for working with video data. This update is completely optional and is meant to be a preview of the optimization work that is currently under development for the next release of Premiere Pro."