Jailbreaking a new iPhone OS device is almost a race these days, but we never expected the hackers to break through the iPad's security in one day. And yet, that's exactly what they've done.
MuscleNerd, an apparently well-known member of the iPhone Dev Team (the group of tinkerers responsible for most of the jailbreaking of the iPhone and iPod Touch), managed to use a similar technique with the iPad as with the iPhone for a preliminary jailbreak. The hack seems to be a browser-based exploit that allows the user to get root access, which in turn allows that user to install whatever software he or she wants.
This is still an early hack, meaning neither you nor I can really do it on our own iPads. But given the iPhone Dev Team's past, they should release a near idiot-proof piece of software that'll jailbreak the iPad in a simple click or two, and probably fairly soon.
Jailbreaking allows for all kinds of uses of which Apple doesn't approve, from illegal or unsavory apps (including emulators and porn) to aesthetic customizations (wallpaper, widgets) to battery-draining activities (multitasking). Jay Freeman, founder of Cydia (sort of an open-source app store for jailbreak apps) estimates 8.5% of all iPhones and iPods Touch are jailbroken--and given the possibilities with the iPad's crazy battery life and powerful processor, we could see some really impressive jailbreak apps. We'll update when it becomes easy for normal people to jailbreak their iPads.