As requested, a list of sprite resources, feel free to add your own..
No idea which of these you need to get permission for, you'll have to read the sites..
* Links to good RPG Maker sites http://www.geocities.com/rpgmlinks/resources_2000.html
* Assorted sprite packs and links to some morehttp://www.cs.uu.nl/people/markov/gmaker/resource.html
* Piles of average spriteshttp://www.molotov.nu/?page=graphics
* A ridiculous amount of isometric character sprites (with animations)http://www.reinerstileset.4players.de:1059/englisch.htm
* A few odds and sods I've used in the pasthttp://gfg.members.beeb.net/
* Gameboy counter strike sprites http://mapage.noos.fr/totitch/Sprites.html#
* A good collection of sprite ripshttp://tsgk.captainn.net/sprites_snes.html
Hope this is useful,