If jailbreaking means accepting a slightly lower standard of stability (which is debatable to begin with), it just isn't as crucial as on your phone. After all, the iPad is a device begging to be treated more like a computer than a phone, and jailbreaking makes that much more possible than Apple's approved software possibly can.
I for one am willing to sacrifice a little polish for functionality on the iPad.
It is worth noting, however, that multitasking will come to the iPad with Apple's blessing, albeit in a limited form, with this fall's release of iPhone OS 4.
Now, because of the nature of the software available through Cydia, it's important to remember that not everything originally written for iPhone/iPod Touch works with the iPad.
Be sure to consult the Google Docs spreadsheet created by iPhone Dev Team member MuscleNerd, before you install anything through Cydia. If you stick to this list, you should be safe. And if you like to live dangerously, remember that you can always restore and be right back where you started if need be (and don't forget to make a note in the Google Doc about what happened!). We’ve set up a page on our Wiki to keep track of compatible apps, too.
My favourite jailbreak programs right now (on both iPhone and iPad) are Notifier, a little extension that puts icons in your status bar for new email, messages, etc, SBSettings, a little panel of useful controls that slides down from the status bar, even within other apps, and Backgrounder (source code), so you can listen to Pandora while you draft an email (for instance).
Another one of particular interest to iPad users is called FullForce, and is a convenient, packaged implementation of an elaborate .plist hack (via Gizmodo) that lets iPhone apps format themselves for the iPad's screen without pixel doubling. It isn't perfect, but works spectacularly for many apps, including Facebook and the New York Times.
These programs don’t all have sites of their own, but you can find them in Cydia on your jailbroken iDevice, along with description and screenshots.
For those of you planning to jailbreak, once you do, don't forget to back up your SHSH ‘blobs,’ the hashes iTunes checks when you restore, so you can restore to this jailbreakable version of the OS even after Apple updates it, closes the jailbreak vulnerability, and stops signing restores of OS 3.2. This way, if you ever need/want to restore to an earlier version of the OS, it’s straightforward to trick iTunes with the backed up ‘blobs.’ Saurik, famed in the jailbreak community for creating Cydia, has a good explanation along with detailed instructions on doing this on his site.
Once you're jailbroken, it's easiest just to back them up through Cydia. Alternatively, this method, using a program called Firmware Umbrella, works whether or not you are jailbroken, and is a good idea if you haven't yet but think you might want to in the future.
Finally, do keep in mind that jailbreaking voids your warranty as far as Apple is concerned, so always restore to an un-jailbroken state before taking your device to Apple for service.