Webman comes with button binds, I don't recommend that you turn off fan control as it helps out dramatically.
Hold L3 + R2 + START while you're in the xmb to toggle it on/off
Depends on the console. For the Fat PS3 you may want to leave on dynamic fan control and tweak with the settings to your liking. However the Slim PS3 fan will function better on its own with dynamic fan control off. As for me I use a small table fan for my Slim PS3 and laptop so both always stay at a low temp.