I'm know that the actual exploit has been posted many times (just search on Netherspace, Prince, etc), however, when I tried to show my brother this little trick the other day I found myself unable to follow my normal route to Prince. Apparently Blizzard has added a few extra "invisible" walls down there, making it HELL to actually get back there.
Its still doable, just very very hard now.
EDIT: For those who don't know the Netherspace Exploit, here it is: [ame]http://www.youtube.com/watch?v=aor_tPZ8ukQ[/ame]
This was the harder way to do it, but it gets the point across.