How do I switch my user agent in Chrome?

I'm not aware of any extensions that allow you to input a custom string, however you can specify a custom user agent on the program's command line.

Right-click Chrome's shortcut and select properties, then add the --user-agent switch to the command.

e.g.:

From a website's perspective ( www.useragentstring.com ):

Google Chrome has no API that allows you to modify the HTTP headers as of yet, so extensions rely on the Javascript method. Any website that parses the agent from HTTP headers will see past that extension anyways. This may be one of the reasons a developer has not spent time creating a user agent switcher that allows custom agents.

On OSX you can launch from command line like this.

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --user-agent="Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; Molla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 3.5.30729)"