haha, i was _just_ about to say that, Transient! But before any one doubts you, i will confirm that this is true; Cat5e is sufficient for gigabit networks. most cables are cat5e instead of just cat5. i know the original poster said he's familiar with setting up a crossover connection, but for the n00bs I'll give a quick overview:
in the ps3 open the network settings and choose manual settings.
set the ip address to a private ip address 192.168.0.5, for example.
set the subnet mask to 255.255.255.0
i think when i tried this the ps3 wouldnt let me continue at this point unless i entered a default gateway and dns server ip address, but on the pc you can leave these blank. you can just use the ip address of your computer for both if you want.
on the pc, open your control panel and go to network connections. right click on your wired nic. choose properties, ipv4 settings, change from dhcp to static/manual.
set the ip address to private ip address on the same subnet at ps3, i.e.
match the subnet mask to the ps3's, i.e. 255.255.255.0
leave the default gateway and dns server blank.
hope someone finds this useful.