Thanks for providing the helpful info. Her are the short instructions:
1. If you don't need the latest version of memcached, you can use already precompiled rpm package for it. Run as root in the shell:
2. Its startup configuration may be adjusted via /etc/sysconfig/memcached file. To start memcached run:
/etc/init.d/memcached start
3. To install PHP Memcached extension:
mkdir /root/setup
cd /root/setup
wget
http://pecl.php.net/get/memcachetar -zxf ./memcache
cd memcache-*
phpize && ./configure --enable-memcache && make && make install
4. It should be activated in your php.ini as well via editing /usr/local/lib/php.ini and adding the line "extension=memcache.so" under the listing of other extensions.
Something like about should work. Unfortunately, I got those instructions from head as don't have a machine to test right now. Please advise, if you get any further questions.