You could try using:
PHP Code:
<?php echo get_the_excerpt(); ?>
I think that strips all HTML and doesn't wrap paragraph tags around the excerpt, but I could be mistaken. If you do get paragraph tags using the above you can just use
PHP Code:
echo preg_replace('~</?p>~i', '', get_the_excerpt());
You could also look into using a plugin to apply a filter to the calls to
the_excerpt() which would negate any need to edit the template file(s).