Hold down the icon until it starts to wiggle. Tap the X in the top left corner of the icon. When you have delete all the apps you want, tap the Home button to exit edit mode.
If the app was synced with iTunes on your computer, it will still be there. You can leave it there as a reminder in case you decide to try the app again later, for easy reinstall later, or maybe loading it on another iOS device (using the same iTunes account). Or you can delete it off of iTunes. Delteting it out of iTunes will not effect your ability to download it again later with out being charged.