I have a watch button in my free nodelet:

<br>
<form method="post" action="?" ><input type="hidden" name="message" va
+lue="/msg watcher watch `id`" ><input type="hidden" name="op" value="
+message" ><input type="hidden" name="node_id" value="`id`" ><input ty
+pe="submit" value="Watch" ></form>  
<form method="post" action="?" ><input type="hidden" name="message" va
+lue="/msg watcher unwatch `id`" ><input type="hidden" name="op" value
+="message" ><input type="hidden" name="node_id" value="`id`" ><input 
+type="submit" value="Unwatch" ></form>
[download]