geturl on as 3.0

You can use Code Snippets in CS5

/* Click to Go to Web Page
Clicking on the specified symbol instance loads the URL in a new browser window.

Instructions:
1. Replace http://www.adobe.com with the desired URL address.
   Keep the quotation marks ("").
*/

myButton.addEventListener(MouseEvent.CLICK, fl_ClickToGoToWebPage);

function fl_ClickToGoToWebPage(event:MouseEvent):void
{
   navigateToURL(new URLRequest("http://www.adobe.com"), "_blank");
}

Please indicate if this is helpful.

use navigateToURL().