Newbie firewall question

[Nicolas]

Hello.
I have just installed 5.2 on my machine and everything works. Now I am 
trying to configure it and I want to put up a firewall but a everything 
I read seem to refer to a dial up connection, I have a LAN connection.So 
my question(s) is: is there a difference between a firewall for a dial 
up connection and a  Lan connection.? And if so what is the difference, 
where can I read about it and is there any good sites to look at? I have 
The Complete FreeBSD, the handbook, Absolute FreeBSD......
I would be very grateful for some help or directions where to look.
Many Thanks!!