You must have noticed sometimes that when you click on a link in Google Search or Google News, it will take you to the password protected webpage of some premium website or forum which usually requires a paid subscription or free registration. You can now bypass such restrictions imposed by posing as GoogleBot when visiting such websites by changing the user string agent sent by the type of web browser you may be using- Opera, Firefox or Internet Explorer 7 to:

User Agent: Googlebot/2.1
Compatible: http://www.googlebot.com/bot.html

I have reproduced below methods to change the user agent string of each web browser:

1) Internet Explorer 7

Save the following text as a .reg file and double click on it to import it into the registry

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\5.0\User Agent]
@=”Googlebot/2.1″
“Compatible”=”+http://www.googlebot.com/bot.html”

To undo the changes, save the following text in a .reg format and import it

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\5.0\User Agent]
@=”Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)”

2) For Mozilla Firefox 1.5 or later, you can download a free addon called User Agent Switcher here and add the custom header conviniently.

3) For Opera 9.0 or later, there is no way to change the user agent string completely, unfortunately. Therefore you will need to use a third party solution called Proxomitron(download link).
Once you download and install Proxomitron, follow this guide to change the HTTP header filter in the applciation. Once that is done, goto Opera preferences–>Advanced–>Network–>Proxy Servers and under HTTP, enter “localhost” and for port enter “8080″.