They come in different sizes. And yes you can delete them and ITunes will remember that you already downloaded it so you won't have to pay for it again.
You can delete them right on the iPad by pressing on the particular app icon and leaving your finger there for a few seconds until the icon starts to shake and a red X appears next to it on the corner.
Another way and better way is to connect your iPad to the computer and click on the iPad in iTunes, go to apps and put a check mark on the apps that you would like to sync and click on "Apply".
depends on the ipad apps size
like the whos here app takes like 9mb space on computer and on ipad lol
and yes you can delete them from itunes and your ipad
Thanks, thinking of getting one but would only be able to get the 16gb one, that's alright then. :]