First, a question: Why do you want to do that? Your firewall is an essential component of your internet security. Your computer can get compromised within minuts after you connect without one, without any need for you to navigate the web, or even to have any browser open. Just having the computer on and connected is all that it takes.
Maybe it's a malicious application trying to call home. In that case, you ABSOLUTELY DON'T want it to connect!!!!!!!!
It's preferable to set exceptions.
Assuming you are running Windows:
Open your controll panel.
Double click "Windows firewall"
Click the Exceptions tab.
If an application can't access the internet, AND it's not listed, click the "Add a program" button.
Sellect the name of the program or navigate to the executable you want.
Click OK
If the name IS in the list but unchecked, add a check mark for that program.
Click OK to finish.
If you still want to disable your firewall, then, in the same dialog, on the General tab:
Check the box "Disabled (not recomended)"
Click OK
Your firewall is now disabled, and good luck, you'll realy need all the luck you can have.
Then again, disabling your firewall is realy NOT a good idea, nor a wise one.
Kualinar, March 2010