Wisdom taken from here: http://wordpress.org/support/topic/how-to-get-the-url-of-the-page-you-are-on-with-php

echo "http://" . $_SERVER['HTTP_HOST']  . $_SERVER['REQUEST_URI'];

If you are in the WordPress loop:

Yes it will work for lists of posts, providing they use a regular loop..

the_permalink() is a loop function, it’s made for use “in the loop”.

If you have a non-standard loop, you can just as easily use…

echo get_permalink($ID); where $ID is a variable where you’re storing the ID for the “current” page/post in your custom loop or you can again use this with a single entry, just as long as you pass the ID into the fucntion.