1. There's a Print and Sharing app you can download. You can open a browser on a PC on your network and copy files to the iPad like it's a storage device (just like AirSharing on the iPhone), and you can print from there. I bet iWork has print capability also, need to investigate that.
2. There's an overprice adapter for the iPad that either accepts your camera's USB cable or an SD card (latter is useless for me and photo pros, we all use CF cards...). Also, #1 above is an option. So is emailing them to yourself (I know... I know...)
3. Somebody else answered that very well I think, if I read the replies right.
4. Sorry, that's a workflow issue you need to work out for yourself. But keep in mind that the 4.0 OS coming out for iPhone and iPad will support folders for apps finally... small but useful step in the right direction.