to call a number[default tel app] or place a skype chat[skype app], can you tell me URLs for more he

[Leonidas Savvides]

	public static void call(Activity activity) {
		Intent intent = new Intent(Intent.ACTION_CALL);
		intent.setData(Uri.parse("tel:[phone]"));
		activity.startActivity(intent);
	}
	public static void skype(Activity activity)
	{
		Intent intent = new Intent(Intent.SKYPE_CALL);
		intent.setData(Uri.parse("skype:lsedfr"));
		activity.startActivity(intent);
	}	

to call a number[default tel app] or place a skype chat[skype app], can you tell me URLs for more help[sample code]?