I think best bet would be to just get a cat 5 cable (standard ethernet cable)
Cat5 = 100mbps, this means data is transfered at a reasonable rate, good enough for pms to stream 1080p.
Cat5e and Cat6 = 1gbps, what this means is: Can transfer data faster, means videos will stream faster BUT require your router and PC to have 1gbps cards, pretty sure these are backward compatible.
Crossover: PC to PS3 directly is what this TYPE is used for
Patch/Straighthrough: Will connect PC to router, PS3 to router.
But seeing as you do not know much, i think just buy cat5 (patch/straight through) cable as it will be easiest for you.
( ----- is cat5 cable)
Hook PC up to router
Hook PS3 upto router
your DHCP on the router (assigns IP's) will do the magic for you.
Should work straight away.
magic is done