(make sure you dont download 64 bit platform loader if you are on 32 bit).. and then of course you need
packages...if you have yum installed, you can install via
yum install zlib zlib-devel
Ioncube installation is easy... you can do it via php.ini file using zend_extension set-up or you can load ioncube on the fly..... unless you have disabled dl or ds function, dont remember exactly anyway, ioncube have a good howto for set-up
I checked the download page of the php-accelerator website and don't see anything about 32 or 64 bit or a loader, even not in the quick install file.... But the worst thing: I don't see CentOS in the dowloadn-list....