So when I google search what is my IP the websites give me a different number then if I look at my IP address through the Network Preferences. I am running a macbook pro with osx 10.6.8
Because you ISP (Internet Service Provider) provides you with an IP address for travelling the www, while your computer also has an internal IP address for travelling the local network you have, which may only consist of modem, router (which sets the rules for internal IP addresses, normally 192.168.0/1.1 or 10.0.0/1.1) and Mac.
In other words, everything is fine and you haven't been hacked. Maybe have a look here, to learn more about IP addresses.
No, they shouldn't and can't match. My AirPort currently has the address 10.0.1.2, but it could also be 192.168.0.2, but if that would be the same address I get when using the WWW, there would be millions, maybe billions, of conflicts, as 192.168.x.y and 10.0.x.y are reserved for internal IPs, and your ISP gives you an external IP, which is probably dynamic anyway.