Just three bits of code stolen from various places on the web:
<%= text_field_tag 'login' %>
<%= password_field_tag 'password' %>
<%= submit_tag 'Log in' %>
<%=link_to 'Signup', {:action => 'signup'}%> <%= end_form_tag %> <% form_tag do %>
Please log in.
<%= text_field_tag 'login' %>
<%= password_field_tag 'password' %>
<%= submit_tag 'login' %>
<% end_form %>