welcome

if you're looking for already made sprites for your game, you'd do better going to the gallery, looking wich ones would you like to use and ask the author if you can either use them or ask him if he can make you some. some might not have problem to lend them for free, some might not, but thats up to each one.

these drawings are made with the hard work and patience of each one has put  on them.

the software you use its almost irrelevant as long as it allows you to use non automatic autoaliased brushes, and guess foreworks works for that(although you can always go ahead and use paint if everything else fails).

as for tutorials, i often like to recomend gas13's one-a nice and complete guide to every basic element you need to know to start.