Custom Field Value only if populated

I need to show a custom field in posts, with some text before it, but I don’t want to show the text if the custom field is empty. I tried some code from wprecipes but it was showing the text before it even when the field wasn’t added, then I checked the Docs but it was too confusing because it doesn’t mention how to add echo ‘some text here’ before the field values.

I need to somehow detect if the field is added and only show that text if it’s added to the post, and if not, then hide that text.

For instance, I want to add “First published in Some Publication Name Jan 2010“

I wanted to create a custom field value key named ‘publication’ where the text ‘First Published in’ is automatically populated so the admin doesn’t have to add that to the value box. I was thinking of adding echo ‘First published in’; to the code in the Loop somehow.

Does anyone know of any tutorials or code that I can use in the latest version of WP?

Thanks!~