It would be good to have some basic AI over the slashes. For example, in case when there are double slashes: '/home//httpd/foobar' - it has to be treated the same way as '/home/httpd/foobar' and maybe also '/home/httpd/foobar/', although I'm not sure for the latter.
Also, beside the ArrayIterator interface, a public $length (count) variable/method would be handy.
Otherwise, it might be really cool if you're planning to add in the future some utility functions such as:
- converting relative to absolute path and vice versa;
- finding the greatest common parent of two paths;
- comparing paths;
- providing the relative path from one path to another, for example: $p->diff('/home/httpd/foobar', '/home/foo') to give '../../foo';