Originally Posted by I_bRAD
Here's a seatpost trick I came up with a few years ago when trying to remove stubborn seatpost so I could ship my friend in Sweden his favourite ride:
If the seatpost has the micro adjust style (2 bolts and a curved section for adjustment, like on a Thomson) You can remove the saddle, and flip the top piece over so you now have a handy clamp arrangement. Stick an old flat handlebar in there (or any sufficiently long cylindrical item), clamp it down and presto you've got 2' of leverage to twist it out.
Disclaimer: I've done this and it works, but I have no idea at what point you simply break something!
I suppose if you didn't care about the seatpost you could also just use a pipe wrench to get some leverage.
This is a fine method if the post isn't stuck really bad. You could literally twist the whole seatube if you put too much grease in the elbow. Give it a go...if it doesn't move with some decent oomph don't keep trying...it can screw the frame up. Spray lubricants/anti seizing products are yer friend.