is there an iPad virus?

Can you get an iPad virus if Jailbroken? Yes. Is there any viruses? No. As long as you have your SSH passwords changed, or don't have OpenSSH installed at all, you aren't in any danger of viruses. Just make sure you use trusted repositories in Cydia. The default ones are the ones you can trust the MOST. Although, xsellize, steffwize, sinfuliphonerepo, podulo, and hackulous can be trusted. Most of those distribute cracked applications so I didn't post the repo address. But, from those repos that you have to add on your own, be careful what you install, they aren't taken care of as the default repositories. Do not install something that you already have from another repo, make sure not to install and Mobile Substrate things, or Simulated Key Events from podulo, because that will cause a restore. Some things can mess up your device, if you don't know what your doing, such as if the developer forgot to update the app or description, it might work on an older FW version but not on the current, and might cause a restore on the current FW. Just be careful what you install is all.

There is no iPad virus if it is not jailbroken because Apple screens all of the apps before approving it.

But an jailbroken iPad can get a virus since you are jumping the approval process.

Theoretically you could get a virus the same as you would with any computer. It would be extremely difficult to design a virus for iOS 4 that would target a huge number of users at this point though. You would have to get them to go to a specific website with their device and that is extremely difficult to do. It would not make sense to write a virus for any of Apple's mobile devices. And before you fanboys jump all over this and say that Apple products do not get virus, you are wrong. There is plenty of documented evidence that show that they do (Although I have not heard of a virus infecting any of the mobile devices at this point but it could happen, it is unlikely but still a possibility). Yes, it is difficult to get one and Apple does an excellent job of staying on top of these things but it does still happen.

if you are jailbroken yes it is possible yes if not i dont think its possible