Is there an application for sharing music like kazaa or imesh on ipad

I understand this could be used for legal purposes but 9 outta 10times, it leads to piracy.

Not officially without a jailbreak at least. What you can do os run a web based P2P client on your local network and access it from your iPad. That's what I do for torrents using Transmission's web interface. I'm sure there's some GNUTella clients out there that offer something similar.

Pair that with something like AirVideo or Files Connect / FileBrowser and it's as good as having the clients on your iPad; in fact it's better since all your media is stored on a network share and not consuming the iPad's meager storage.