Use a bumper jack. Or make one out of some scrap metal. Just need a upright of some sort, a pivot point, and a lever.

Or, one of several different ones out there:

http://www.northerntool.com/shop/tools/product_13224_13224?cm_ven=Aggregates&cm_cat=Google&cm_pla=Farm%20%2B%20Acreage%3EFences%20%2B%20Gates&cm_ite=143962?ci_src=14110944&ci_sku=143962

http://www.hi-lift.com/post-popper/index.html

I've seen a tool to lift those posts. It was just a pivoting lever on a base. The up-right was was about 12 to 16 inches tall with a bar the was off center and fit into the metal posts holes with the other end of the lever having a place to plant your foot and push down to lift the post. It only lifted the post about 6 inches or a bit more but once or twice and you could just pull it right our of the ground easily. Can't remember the right dimensions but it was a dead simple tool. Give you any ideas? Maybe you can reinvent it!

I used to keep a commercial bumper jack that I picked up for nothing for that job. A Short piece of chain just wrapped and tied worked for that job. I pulled a lot of old fence post. With longer chain and shackles I used it as a come along.It made a good compactor too. I used it to raise an old motor block enough to get it on a sledge. That free jack sure was handy. I wonder what happened to it. Probably not OSHA approved.

Shannon --- Aw, did you have to? Now he's going to want one...

Vester --- I like your idea of Mark reinventing the post puller!

Old fool --- Yup, Mark's going to want one of those too...