It is very easy to use Dropbox in your iPad.
You have to download the Dropbox app from this website:
www.dropbox.com/ipad
With Dropbox you have a folder with your files (pictures, mp3, work, etc) in your computer or tablet that you can access from everywhere with internet access.
You can also share some folders of your Dropbox with your friends in a safe way.
Dropbox is free and you get a personal space of 2Gb. You can also upgrade to 50Gb of space for $99 per year or even to 150 GB for $199 per year.