See what apps are accessing the internet?

Is there a tracker, firewall or other app that will tell me what other apps are accessing the internet?

I just went to update BatteryTime Lite and it wants full internet access. Why? I have no idea, but it got me to thinking and I looked at a sampling of other apps that shouldn't really need to access the internet, but do. In fact, they all seem to have that access.

I'd like to see if any of these apps may be phoning home....

I did some searching here and on google. I'm sure it's out there, but I was apparently a search idiot tonight.