http://www.jjenv.com/oil-tank-remova...ement-oil-tank
Includes a seven minute instructional video made by J & J Environmental in Pennsylvania. Talks about sawzall blades, kitty litter, what and how to do it responsibly if you don't want to spend your money to hire their removal service.
Craigslist-NH has a number of used oil tanks offered for free in their free section so offering it for free probably does not work.