this is how i interperate it, so dont really take my note for much..
but when you echo you usually echo html code..
eg: echo "<h1>Hello World</h1>" or something like that, whereas print has many different options with it, like printf and many others. i think there is a html CHM file (like a help file) that you can download somewhere here that will explain it better.
Hope im right, and if i am, i hope i was a little help..