Carrier IQ is an insanely invasive bit of software, and it’s on at least 100 million phones, entirely without the owners’ knowledge.

If you use an Android device, there’s now a simple way to find out if Carrier IQ is already installed on your phone.

We first showed you how Carrier IQ works earlier this week. Basically, it’s low-level mobile ware that tracks everything you do — your apps, your phone calls, your locations and even your text messages, perhaps keystroke by keystroke — and then stores the data and sends it to your mobile carrier.

One mobile developer, Trevor Eckhart, took it upon himself to find out how Carrier IQ actually works, and the Internet has been in an uproar over the blatant invasion of privacy ever since.

We wouldn’t be sounding the alarm about this software if it wasn’t incredibly widespread. In early 2009, when Carrier IQ was raising a $20 million finding round, the company said its software was already installed on 35 million cell phones through seven mobile vendors.

However, by the middle of last year, when the company raised another $12 million round, it told VentureBeat its software had been deployed on more than 90 million mobile devices by 12 leading vendors worldwide.

So if you’re concerned about your privacy or if you just want to know whether or not Carrier IQ is on your Android phone, here’s the app to check out: Carrier IQ Detector [Android Market link].

This new app comes from Lookout Labs, a mobile security firm. Lookout’s Tim Wyatt writes, “While there are a number of blogs that have posted instructions on how to detect and/or remove Carrier IQ software, these are largely technical in nature and difficult for the average user to follow.”

Wyatt notes that it is still unclear just how invasive or unwarranted Carrier IQ’s tracking of data might be, but he does say, “We’re encouraged that the mobile community is paying increasing attention to privacy risks associated with their mobile data.”

While knowing whether or not you’re currently running Carrier IQ is half the battle, actually getting the software off your phone is, especially for the less technical, an almost impossible task involving rooting the phone and installing a new mobile OS. Several guides for Carrier IQ removal are available online, but perhaps the best course of action is for consumers to raise a stink about the software, get carriers’ attention, and force these companies to take our collective privacy a bit more seriously in the future.