Download and install the User Agent Switcher from here
Read popular magazines for free as a IPhone
Zinio is a company that is providing popular magazines like Reader's Digest, CosmoGirl, Elle, Macworld, Men's Health, National Geographic, Playboy, Penthouse and books in a digital format for free. These magazines are served as high resolution images and are the exact replica of the real magazines.
To read these magazines inside Firefox, first download User Agent switcher addon for Firefox. Go to Tools>User Agent Switcher>Options >Options. Click on User Agents and then click on Add. Now fill in the fields as follows:
User Agent: Mobile Safari 1.1.3 (iPhone; U; CPU like Mac OS X; en)
App Name: AppleWebKit/420+ (KHTML, like Gecko)
App Version: Version/3.0
Platform: Mobile/1A542a Safari/419.3
So we have added iPhone as a user agent. Then click on Tools>User Agent Switcher and click iPhone to set the user agent to iPhone. We are now ready to begin.
Proceed to http://imgs.zinio.com/iphone/ and read all your favorite magazines for free!
Walk in google shoes
Well, the googlebot is allowed access to webpages that are normally restricted to registered users (members-only sites). This is mainly because the site owners want their websites to be searchable via google but at the same time preventing non-members from accessing.
Go to Tools>User Agent Switcher>Options >Options. Click on User Agents and then click on Add. Now fill in the fields as follows:
User Agent: Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
App Name: Googlebot
App Version: 2.1
You are done, congrats, your browser will now be recognised as a googlebot!
To revert back, click on Tools–>User Agent Switcher–>Default