When are Apache modules loaded? I recall which i read somewhere that some modules are loaded in the server startup, while some are loaded before long therefore the startup wouldn't decelerate. And if the administrator desired to load a brand new module in the runtime, how's so now?

I believe you're mentioning to Dynamic Shared Object (DSO) modules. There's lots of good information on these within the Apache Server documentation:

http://httpd.apache.org/docs/2.2/dso.html

Regrettably, even if using DSO modules, you've still got to restart the Apache server to be able to load a brand new module. There's presently no way of loading of Apache modules as the server is running.