http://esr.ibiblio.org/?p=1192#more-1192
ADDED: Even if you disagree with ESR's take, and many will, this is the clearest definition I have seen on what qualia is. So it should present a useful starting point, even for those who strongly disagree, to argue from.
Downvoted for lack of description of the (topic of the) link.
Seconded, I also downvoted for lack of summary. And ESR is known for talking out of his ass, so I'm not going to bother reading that unless I'm sure this is much more insightful than his typical writing.