Combining custom fields into one sentence.

I have a Photoblog, and many of the photos that are posted are sent from various sources.
Each post has 4 custom fields:
Photographer
Photographer’s site
Location
Keywords.

Using <p class=”postmetadata alt”> , I’ve managed to show all those fields in the post, but I’m trying to combine the first three keys in one sentence , something like:

Photographed by _______ on location:_______
(The first blank space should include the combined photographer’s name and site link, and the second blank space should include the location key value)

And than, on the next line I want to show only the value of the fourth field (Keywords)

Having no experience as a web developer, I have no idea how to write the php statement.

Can anyone help me here?

Thanks.