How can I login to icloud.com from my iPhone?
This is not possible, nor was it possible with Mobile Me.  Particularly irritating when a number of people share an iPad and don't want to enable full email for each other for example.  I'm afraid there is no way around it, unless perhaps you can download a different browser from the App Store that will enable you to change your user agent string to trick the website into thinking you are using Firefox or something that isn't mobile safari.