Identifying a mystery celebrity in a photo, or finding websites that have stolen your copyrighted images has gotten a whole lot easier with Google’s Search by Image. Images can be dragged and dropped, uploaded, specified by URL, or (with a Chrome or Firefox extension) simply right-clicked. To see Dave Taylor ID a mysterious blonde, read Can I Identify a Photo Using Image Search?.

This week, Skype, the voice and video chat application, announced Skype in the Classroom, a free service to help teachers connect their classrooms with other classrooms around the world. With 4800 teachers already signed up, teachers can find partner classrooms by searching geographically or by project. Project postings summarize the kind of interaction teachers are looking for, and can be filtered by age, language, subject or type.

A screencast is a video of a computer screen, and can be a useful tool for demonstrating software, teaching or training. I’ve used Camtasia for years, but it is expensive. I’ve also heard great things about Jing, which is available in both a free and a pro version. To learn more, Lifehacker Jason Fitzpatrick lists Five Best Screencasting Tools in his article of the same title.

Although it is still only available with an invite from an existing user, Google Voice recently opened up their free voice mail service for use with your existing phone number. With Google voice mail, you get voice mail messages with attached audio files delivered to your email inbox along with a transcription of most messages, so you can read what your voice mail says. Watch a video of these features at Google Voice .

Although Google creates wonderful, free products that so many of us love and use, from a purely information management viewpoint, we should all be a bit more concerned with data portability. And Google agrees! The Data Liberation Front is an engineering team at Google whose one goal is to make it easier for users to move their data in and out of various Google products. Learn more at The Data Liberation Front.

Cable clutter is the bane of the modern desk. This tip from the Closet Entrepreneur offers instruction on how to use a simple daisy chain (or chain sinnet) to tame stray cables and power cords. The article includes a video that shows a slightly different method for long extension cords.

Free Wi-Fi hotspots can usually be found at public libraries, Barnes & Noble and McDonald’s. But there is no reason to limit yourself to these well-known spots. In her “Definitive Guide to Finding Free Wi-Fi” Gina Trapini lists free tools for Windows, Mac and smartphones for finding public hotspots wherever you may roam.

If you’ve never tried mind mapping as a brainstorming tool, the free version of Mind Meister is a great place to start. Mind Meister is an online tool used in a browser, but your maps can be published to any website or exported as an image or PDF. Although you are limited to just six mind maps in the free version, teachers and students can upgrade to the Academic version for just $15 a year.

If you’ve never created a personalized homepage, or custom start-up page for your browser, there are a lot to choose from. My personal favorite is iGoogle but Pageflakes looks interesting too. A custom homepages is a place to gather all the news, feeds, email, gadgets, widgets and apps that are important to you, to give you a single place to start your web sessions from. For a closer look at fourteen different homepage services, read Mashable.

When visitors to my home office see the two large monitors on my desktop, and see the mouse travel seamlessly from one to the other, they are usually amazed to learn that support for multiple monitors is built into Windows. All you need is multiple outputs from your video card, or multiple video cards. To learn more, read Ask Leo’s How Do I Set up a System with More than One Screen?.