According to Foreword This Week,
UClick, a content distribution company owned by Andrews McMeel Universal, the parent company of Andrews McMeel Publishing and the Universal Press Syndicate, has developed iPhone apps that display comic books one panel at a time, the way they were first created. Each app costs $.99 and titles including Bone, Ghostbusters, We the Robots, and Basic Instructions are available.
But of course there's more than UClick out there. Check out these other iPhone apps for comics: