first, you need to jailbreak your iPhone, although 2.0.1 jailbreak isn't out just yet afait
then, you need to hack it to run apps originally for other iPhones
then, get a hacked version of netshare from somewhere
then, SSH it onto the device
done
sure as long as that person is willing to post there iTunes store acct. info
Little thing called DRM, Apple uses it on all the App Store Apps to keep a leash on them.
which means you have to auth to use it. Suspect Apple will wonder why one app is aut'd 5k times