When somebody writes an iPad app which both syncs files with the cloud and lets you edit them, they’ll make a killing at the App Store. Until then, we have workarounds like this one from SugarSync.

SugarSync is an application for Windows, Mac, iPhone, BlackBerry and now the iPad. It works like many cloud-sync apps: You point it at, say, a folder on your computer and when any file is changed or added, it is automatically mirrored in the inter-ether. This means that you not only have an offsite backup but you can access and edit your documents wherever you may be.