I've found this tutorial to install APC on servers with lighttpd + php 5.2 on Ubuntu 10.
However, when I run
sudo pecl install apc the package is just downloaded and is not installed. (i.e. I'm not asked the next question" and apc.ini file is not created at all.
If I run only
pecl install apc I get a warning (no permissions to write some files).
(I need instructions for both 9.04 and 10.04)