Who (generally) voted against (and for)?
As I recall, the vote was expected to be pretty much Everyone-against-the-Tories, and it looks like that's how it ended up. The LDs, SNP and Plaid all said that they didn't think Labour was actually committed to electoral reform but that they would support it on principle anyway. Not sure how the NI parties voted; on the one hand the DUP and the Tories are trying to play nice, but on the other hand, NI already uses STV, so the DUP can't really justify voting against AV for Westminster.
Afleitch is pretty much right about the implications of the switch to AV--would have destroyed the Tories in 1997, but might well destroy Labour if implemented for 2010. Certainly throws the "Labour are evil gerrymanderers and we have to stop AV because it will doom the Tories" Conservatives who are mobbing sites like PoliticalBetting right now. Especially because, if AV really would doom the Tories, surely it is just as much of a gerrymander to support maintaining the current system, which logically would have to have a huge in-built advantage for the Tories if AV, a system not by nature more biased, would destroy them.
Whatever. I'm not a huge fan of Instant Run-Off anyway. Labour are clearly making a disgusting political maneuver here, and the Tories are also making an unpleasant political maneuver (and also a stupid one; supporting AV would lose them nothing). And of course the Lib Dems' and Nats' support for any form of PR has always been at least a little bit self-interested.