AFAIK everything from PHP 5.1.3 on should be fine without modifications in eZ Publish 4.1.3 (did not try with 4.1.4 but I suppose it will work as well). For PHP < 5.1.3 you would need to patch eZ Publish. Also see http://blog.coomanskristof.be/2009/07/15/ez-publish-4-1-3-on-php-5-1-2
This will probably depend from component to component, so far I did not see any issues on the installation I mentioned before here in this thread (just a standard eZ Publish with some pages, not using fancy WebDAV publishing etc.).