Obtaining an ip address

Is there anyway that someone can obtain my ip address. I know that they can see it in the header of my emails, they can see it in netstat if we have a connection, they can see it if they have access to my computer at the time that i am accessing the internet, they can see it from webpage logs. is there any other way that someone might obtain this info and if there is, then are they ways to prevent this from happening via programs and configurations.