At the moment the product page is just a list of specs, but the blog post goes into much more detail, including describing the new RP1 I/O controller:
https://www.raspberrypi.com/news/introducing-raspberry-pi-5/
On pre-ordering:
> We’re also giving every print subscriber to The MagPi and HackSpace magazines a single-use code, giving them priority access to Raspberry Pi 5 hardware.
A subscription is US$43 and up, and gets you a priority code to use at PiShop or The Pi Hut. You pay full price for the RPi 5, but it ships to you first.