I don't have a link handy...but there's a company that produces magnetic action figure display stands...basicly figure stands with magnets in the base...could use those.
I'm not sure just stuffing magnets in a figure's chest would give you the desired look... it'd be cooler to take some button magnets and dremel down into feet, hands or parts of accessories to mount the magents flush with a surface and then stick them to the fridge.
I did somthing similar on the backpack of my Space Ninja Crystal Ball... the Jump connects to the Astro VIper pack with a couple pairs of magnets.
http://img.photobucket.com/albums/v644/ ... inja-6.jpghttp://img.photobucket.com/albums/v644/ ... inja-2.jpg