The PS3 has two methods of connecting to your home router. You can either use an ethernet cable connected from the back of the PS3 to one of the open LAN ports on your router (usually labeled 1, 2, 3 or 4) or connect wirelessly using the PS3 built in wireless adapter.
Sony has detailed instructions meant to assist you connecting the PS3 to your internet connection.
You can access the wired connection settings help page by clicking here or going to http://manuals.playstation.net/document/en/ps3/current/settings/connectwired.html
You can access the wireless connection settings help page by clicking here or going to http://manuals.playstation.net/document/en/ps3/current/settings/connectwireless.html