DVD to iPhone Converter lets you easily rip DVD movies, including commercial DVDs, directly for your iPhone 3G, iPhone 3GS, or iPhone 4.
Simply click "Like" button on iSkysoft's facebook page, choose version you want (PC or Mac) and click 'get keycode button.
P/S: I tried clicking 'download now' straight away and it works too. So you dont have to enter your details/emails.
Need to register to get the keycode though :)