It hit net-2.6.19 today, and now that USAGI's IPSEC layer control plane modifications are mostly out of the way I ported my XFRM hashing patches into net-2.6.19 as well.
It was a "3 double-espresso" all night hacking session.
Plonk!
If you want to beat those airline crooks at their own game, you might want to check out Farecast.
Currently they only handle major cities in the US, but I'm sure they'll add international routes eventually. You can even track a trip with RSS to watch the price changes. It's incredibly cool.
Unfortunately big buisnesses don't like when consumers know a lot, so they might try to make life difficult for these guys.