When linking internally to other pages on your website does it matter which of the following is used in respect to SEO "http://www.mypage.com/page.php" or simply "page.php"
it doesn;t really matter. SE will read the full url anyways. besides, when you do a site map, you don;t use the entire url, its just the file names
I'd stick with one and go full stream ahead http://www.mattcutts.com/blog/seo-advice-url-canonicalization/
I am not sure if there is any difference - web spiders are smart enough to spider links easy. Using full links will increase your page size, thus - generating more bandwidth. This matters for very large sites with millions of pageviews daily.