How do I secure my wireless network?

Hello,

I'm a total newbie when it comes to networking but I do have some experience with computer hardware (I've build several desktops).

So, I just got DSL and bought the D-Link DI-624 Wireless/wired router as well as 2 PCMCIA cards for the two laptops in the house. I've got WEP enabled with 128-bit encryption.

I've got zonealarm installed on all three computers for firewall, but I do not have the firewall on the D-Link enabled (yet). So I was thinking, my computers are safe but what about my DSL line? Will someone driving around still be able to pick up my wireless signal and use my line?

Is it the encryption or the firewall that stops people from using my DSL line? and how do I enable my firewall on my router and still have my brothers go to P2P sites?

Thanks all.

Turn off the SSID broadcast and use mac address filtering...