Poolling

Hi everione!This is my first message!
I want to build a chat, but without this sockets stuff, so i want to learn how polling is done, does anyone knows it?
I mean, i dont want just copy and past a chat, i want to UNDERSTAND how it works!
Besides, kirupa is a great site.I cant imagine how i could have not achieved it before.I will print senocular tutorials about oop and 3d stuff, cos i dont like to read at computer
See ya!