I have
"heard" it is easier to convert a Manual to Auto... But to be honest I have never met anybody who has converted an Auto car to Manual.
I am sure with a nice fully stocked shop and enough money it is possible, it would involve a lot of custom fabrication and you would have to be pretty tricky to get everything to work well.
I am inclined to agree with the other guys though, IMO the huge cost and massive amount of time this will take would not be worth it if you can sell your car and buy or import a manual version of what you want instead. But if this is what you really want to do... well keep us posted