And don't forget to read the "Read before posting" thread (a link can be found in my signature) it answers some basic questions and gives some good links for additional information (such as links to the previously mentioned wiki)
There's been some confusion about how open source the r-pi is. The answer is that the r-pi is open. The only item that is not open source is a little blob on the broadcom GPU, but we've been assured that this is a very low level blob and that the drivers that interact with it will themselves be open source. Part of that closed source also, at this point in times, does include too many details about the chip (such as what chip they're using). This is something out of r-pi's control, so we'll all have to make do with that for now.
The good news is that phones are much the same way (using ARM chips themselves) and people never notice this small bit of enforced closed sourceness
As for schematics of the GPIOs, at this point in time all we've been told is that there are 16 of them. If you'd like to see a labeled layout of the PCB, I made one here, but I don't think that's what you're really looking for in a schematic.
With how busy the r-pi team is getting the product itself ready, I imagine a lot of in and outs will be self discovered then community shared (a task I think most of us are actually hoping for
), but they'll come in due time.