Simple guide to install phplua on CentOS 6.3:
Run these commands in terminal as root:
$yum install php-pear php-devel gcc lua-devel lua-static
$ln -s /usr/include/lua.h /usr/include/lua/lua.h
$pecl install lua-1.0.0
Then edit /etc/php.ini and add the following line below the similar ones:
Finally restart your web server and you should be all done!
I spent days googling around, trying and failing and gathering up what needs to be installed when you just have apache2 and php5 installed and working.
Thus there is this bug preventing pecl from finding lua.h, which is fixed by the symlink created above. The bug is already submitted:
Hope this info helps some body else too!