///////////////////////////////////////////////////
// Actual AS3 clickable-link code:
my_btn.addEventListener(MouseEvent.CLICK, myBtnClicked);

function myBtnClicked(e:MouseEvent):void {
    var url:String = "http://www.example.com/";
    var request:URLRequest = new URLRequest(url);
    try {
        navigateToURL(request, '_blank');
    } catch (e:Error) {
        trace("Error occurred!");
    }
}


///////////////////////////////////////////////////
// Lazy shorthand.  Reminder: navigateToURL SHOULD be in a try/catch
my_btn.addEventListener(MouseEvent.CLICK, myBtnClicked);

function myBtnClicked(e:MouseEvent):void {
    navigateToURL(new URLRequest("http://www.example.com/"));
}


///////////////////////////////////////////////////
// Implementation of Steven Sacks' AS3 getURL class
import net.stevensacks.utils.Web;

my_btn.addEventListener(MouseEvent.CLICK, myBtnClicked);

function myBtnClicked(e:MouseEvent):void {
    Web.getURL("http://www.example.com/");
}

http://www.stevensacks.net/2008/02/06/as3-geturl-solved/

Shown in the source are the actual code, shorthand of the code, and Steven Sacks' simple-but-sweet rendition of getURL done in AS3, which requires the downloadable class from his site.

AS3 getURL / navigateToURL (How to make clickable links in AS3)

link

ActionScript 3