Out of the 2 PECL extensions, memcache, and memcached, i would recommend memcached.
It wraps libmemcached to access your memcached servers unlike, and in my experience has been far better.
Also, just tell the memcached client what type of hashing to use http://uk.php.net/manual/en/memcached.addservers.php
and it will handle everything for you, memcached does a good job by itself of data is replicated around the place so that losing one or some of your memcached servers doesn't ruin your day too much.
EDIT - libmemcached home page. Sadece eklemek için, onun çok çok karanlık büyü gibi kendi tutarlı karma algorithim rulo gerçekten denemeye değer değil