The PHP extension domxml got a lot of memory leak fixes in the last few days. Thanks to Rob Richards, who started looking into it, we hunted down several issues and there shouldn't be any libxml2 related memleaks anymore, at least not any we are aware of :) Furthermore, there is finally a DomDocument->free()
method. It's now possible to free a DomDocument during script-time and not only at script end. If you're processing a lot of XML-Documents in one script, this will really improve your memory usage.
The memleak fixes and DomDocument->free() were merged into the PHP_4_3 branch, therefore they will be available with the next PHP release (Version 4.3.2). If you want to test/use it already now, you can get it from CVS or from snaps.php.net. Anyway, if you plan to use PHP 4.3, I (and others) recommend highly
to use the stable-code from snaps.php.net or from the CVS PHP_4_3 branch, since there were a lot of bugfixes since the 4.3.0 release (4.3.1 was just a security release, with no general bugfixes)