That link is mostly about Photoshop CS5 with only one post specific to Premiere Pro.
Here's the link to the what's new page at Adobe:
http://www.adobe.com/products/premiere/whatsnew/Premiere Pro CS5 is 64-bit only, so it won't run on a 32 bit OS, you will need a 64-bit OS. The same goes for After Effects CS5. Photoshop CS5 continues to provide both 32-bit and 64-bit. I don't remember whether you have the Production Suite or not. But, all future versions of the suite will require a 64-bit OS from here out.
The big change in Premiere Pro CS5 is the 64-bit support and the utilization of the graphics card GPU for accelerated playback and encoding. Currently it only supports GPU acceleration using Nvidia cards with CUDA. There are a number of smaller new features and improvements of existing features like the new ultra keyer for green screen, native support for more formats like Red and Digital SLRs, import and export of Final Cut Pro XML sequences and so forth. It's a decent step up from CS3 but overall an incremental step up from CS4 if you can't take advantage of the 64-bit architecture and the GPU acceleration.