Why not just use the login() function, which provides a link if the visitor is not logged in? If it's in your _main.php file then on every page generated by the skin it'll show up. If you absolutely MUST have the fields available, then wrap it in something like this:

if( is_logged_in() ) {
// do something for logged in people
} else {
// do something for not-logged in people
}

Thanks, that's exactly what I need. Is there a way to put a link to the person's profile when they're logged in, or at least display their name?

Bump... still looking for the code to put in a link to the person's profile with their name.

A link to a logged in user's profile is standard stock stuff.

user_profile_link( 'before', 'after' );

Most of the time 'before' is '<li>' and after is '</li>' but that depends on your skin.

I don't know how to get a logged in user's name.