Photographic freeware:
Irfanview: www.irfanview.com
This is a small, fast image viewer and file manager, with good basic editing functions. It has slide show, thumbnail viewing and batch processing facility. Jackie and I use Irfanview to manage our large Native plants and Weeds Archive.

One of the nice things about irfanview is that you can extend it's abilities with one touch of the keyboard, by opening your image in an external editor. Recently I've taken to using another freeware program called photofiltre as my add on editor.
Photofiltre: www.photofiltre.com
This program has comparable editing ability to the likes of Photoshop elements, Paintshop Pro, Photo Studio and Photo impact, but is (in my opinion) more straightforward and pleasant to use. It also has a wide array of adjustable effect filters - hours of harmless pleasure.
The program does not support layers, but does have multiple undo/redo options.

FastStone Image Viewer: www.FastStone.org
I can't forebear mentioning here another (more recently discovered) viewer/manager. It retains a lot of Irfanview's efficient functionality while introducing an exciting zoom feature and a complete, full screen view, editing mode. It also has a Report mode which allows you to manipulate your files as if you were in your File Manager. Faststone is generally considerably slower than Irfanview, but has some great features and is pleasant to use. Check the screen shot you'll see one of the Moth pages being set up for my Photo Galleries .

Music freeware:
Power tab editor: www.power-tab.net
For guitarists this is a great learning tool. I recommend it for processing the music that I've put up in my Arranging workshop. I am also linking to a large resource in guitar music available in this format on the web. Everything from Chet Atkins pieces to J.S. Bach and all stations in between. The file sizes are small. (4 -12kb!)
You don't need much knowledge of the program to start using it. Once it's loaded onto your computer and you click on a .ptb file, it will come up as you see on the screen shot. You can hit the play button for a midi play back, or print out the notation and tablature. You can gain access to any performance notes etc by opening the view menu and clicking on "performance notes" or "File information."
If you are wanting to create your own music or tune arrangements, you will find, as I did, that it is an amazingly powerful and versatile editor. The data entry is via the guitar tab supplemented by setting the note duration using the music notation. This looked like an unwieldy system to my experienced, music notation editors eyes, but when I tried it, I found it fast and convenient and was soon converted.
The great thing about it is, that many of the symbols: Ties, slides, triplets, repeats, arpeggiated chords, etc, actually work and are reflected in the midi playback. There is also a single click option for playing all your eighth note pairs as swing eights. This is more than you will get with many commercial editors.

Vanbascos karaoke player: www.vanbasco.com
This is a midi player that can change the key of a piece or change the speed without altering the pitch. If you have a multi instrument score, you can also turn tracks on and off independently.

BestPractise : http://www.xs4all.nl/~mp2004/bp/
This audio player will slow down a cd track without altering the pitch. You can also independently alter the pitch to tune to your instrument, or change key. You can also create phrase loops.
