You can, but I'm not exactly sure why you would want to do it this way. You could use a textarea tag and use the split function:
Code:
<%
TextSplit = Split(request.form("txtUserPass", vbcrlf)
Username = TextSplit(0)
Password = TextSplit(1)
%>
<form method="post" action="page.asp">
<textarea name="txtUserPass"></textarea>
</form>