Playstation 3 question

yo everybody. i just bought my playstation3 barely a month ago and it totally rules!!! although i can't seem to connect it online. i have a dsl at home but i do no have a router. is it necessary to buy a router or am i already going to be able to connect to the internet with  my modem? thanks 

After I got my PS3, I tried to connect to the net with the cable that was in my pc. I unpluged it from the pc and put it in the PS3. It didn't work because the PS3 has another MAC Address. So I bought a router, wich is also wireless compatible.

It has a WAN, LAN1, LAN2, LAN3 and LAN4 and wireless. The main cable I put it in WAN, then connected a cable from the router (LAN 1) to the pc. The PS3 is connected through wi-fi, or I can also connect it through cable, in LAN2, 3 or 4. After I installed the router, I called the internet firma and told them the WAN address. And then it worked perfectly.