I recently give answers on OTN forums about Peoplesoft installation on non-certified plateforms. Like usual, non-certified does not mean that won't work, that just means its on your own risk and responsibility.
The first one was Peopletools 8.49 on CentOS 5.3. Since CentOS is a recut of RHEL, and Peoplesoft is certified on RHEL, that should work.
There is some tricky stuff to get it work, but it works. Find out my post here.
The second one was Peopletools 8.50 on Windows XP (32-bits).
Peoplesoft has never been certified as a server (application server, process scheduler and webserver) on Windows XP, however, for learning purpose I can understand the need to install it there. Furthermore, as long as Peoplesoft won't provide the Application Designer tool for an other plateform, Windows is still required to do some tasks (from client side perspective).
From Peopletools 8.50, only 64-bits OS are supported. So, the main question was if that works on a 32-bits XP machine.
Finally, I got it work on Windows XP Pro 32-bits, everything was installed and running fine without any tricky stuff. Find my post here.
Interestingly, the second question makes a remark. All the PT8.50 components provided on edelivery for Windows are 32-bits (you can even read on the certification matrix the need of the 32-bits database libraries...). Knowning Peoplesoft is certified only on 64-bits OS server (W2k3/W2k8), that makes a full 32-bits application certified only on a 64-bits Windows OS. Why such restriction ?
Again, it is not certified. So, keep it for learning purpose only.