I am using a custom field and need it to echo some text, plus the custom field content if it is true. If not, it does nothing. An example would be

Fax Number: ===> the text I want echoed if the field is true
555-555-5555: ===> the custom field if true

Here is what I got. I have tried some variations with "if" and "else" which did not work.

<li><?php echo get_post_meta($post->ID, 'fax_number', true); ?></li>

Thanks.