Removing stuck or seized seatpost?

This happened to the missus' bike not so long ago and none of the methods I've read worked, so I got a 7 foot long sash cramp (woodworking thing) and gripped it with that, and with an unpleasant cracking noise it came loose.
...the point being that it's good to get something with a fucking long lever, like wedge a broom handle under the saddle and then twist the bastard, or maybe turn the bike upside down, get a fat mate to stand on the saddle and then twist the rest of the bike.

Me and My dad used a huge vice attached to a bench, with one of us at each end of the bike giving it some welly until it came loose.