Gugugg,
in etwa so:
<html>
<head>
<title></title>
<script language="JavaScript">
function setSmiley(str) {
var tar = document.getElementById('deineTextArea');
tar.value = tar.value + str;
}
</script>
</head>
<body>
<img src="smiley1.gif" alt=":-)" onclick="setSmiley(this.alt)" />
<form name="deineForm">
<textarea id="deineTextArea">
</textarea>
</form>
</body>
</html>
Gruß, Uschi