type will or won't

http://www.learn-english-online.org/Lesson39/willwont.htm

will (on the spot decisions)

http://www.tolearnenglish.com/exercises/exercise-english-1/exercise-english-703.php

going to: future

http://www.kico4u.de/english/uebungen/aktiv/goingtofuture.htm

will (future)/going to

http://www.englishexercises.org/makeagame/viewgame.asp?id=2836

going to: future positive sentences

http://inglesnanet.com/grammar/goingto.htm

going to: future negative sentences

http://members.iinet.net.au/~adelegc/grammar/going_to/going_to_neg.html