Brad Moulton writes:

I'd like to be able to store and use the "username" captured in a simple login/password DTML method If you use "basic authentication", then the browser will manage the username and send it on any request. You can access it via "AUTHENTICATED_USER".

If your user allows cookies, you can save the username in a cookie. Otherwise, you should look at a session product (FSSession/SQLSession). Dieter