The video above, from Maxwell Shay, walks you through part of the process. It only works after you jailbreak your iPad, something we wholeheartedly recommend you do anyway. Once you've done that, download the iFile app and the Nano terminal text editor from Cydia. That's the easy part.
The hard part involves all kinds of SSH and PLIST file editing. For that, check out Max's written step by step tutorial here. And seriously, this is tricky stuff, so be careful.
It's a neat proof of concept—and of what all iPads should be able to do right out of the box, if only Apple would let it—but once you get through all the grunt work it's also a handy way to share and store files.
HOWEVER: if you're not an experienced jailbreaker, your best option is probably to hold off for now. It wouldn't be surprising to see a much more streamlined approach packaged into an extension or utility in Cydia in the coming weeks. Meaning you'd be able to install this hack directly from the jailbreak store, saving you from a whole mess of potential problems. [Time-More via Wired]