How to make a Gui Button that when it is pressed the user goes to a website?

Yo i wanna make a button named Website and when the player is pressing on it his explorer (Mozilla,Internet Explorer etc...) will open with the link of a pre-choosed link...for example http://www.google.com/ .

//So here is how to make the button (who doesnt know that ;)

if(GUI.Button(Rect(400,600,180,40),"Website")){

//What should i write here??SO it can reject me to a website?

}