sold at home centers. Its a long handled tool that has a wide (14) inch blade on the end so you can really get down on the tool and scrape off the lino. Some will come off nicely and some will require getting down on your knees with a sharp wood chisel and going that route.
This is not easy and there are not any solvents to my knowledge that will make the task easier. The ones I know will damage the wood.
So, try it and if its too dificult, then go to plan B which is to re lino that room.