Welcome to the official site of Portable Keyboard Layout! This open source program by Máté FARKAS helps people to learn better, more efficient keyboard layouts and then use them anywhere, anytime, even on someone else's computer. If you want to stave off RSI (Repetitive Strain Injury) and CTS (Carpal Tunnel Syndrome) - try one of the scientificially designed keyboard layouts such as Dvorak, Colemak, or Asset and take it with you on a flash drive using PKL. You can also use your favorite national layout - Russian, Hebrew, Greek or some other language - without installing it on the computer that you have to use (in an Internet Cafe, at school, or somewhere else).
It's quite easy to start using PKL, especially if you are trying to learn a new layout and need some reminders about key positions: download the program itself and some ready-made layouts, then check a few settings in the pkl.ini file (they are well documented inside) - and launch the program. If you want to take it with you to some computer that doesn't have any alternative layouts installed - just copy it to a flash drive and launch it when you need it, there is no installation, it's ready to use immediately. Currently PKL supports only Windows-based computers, so don't expect it to work on Linux or Mac, though.
PKL allows for some pretty sophisticated manipulation of key modifiers and keyboard states, so entering even most complex characters is a pleasure - various diacritics/accents, special characters, etc present no problem. It's also quite friendly to other users: if you keep forgetting to exit it when you leave - you can set it to auto-disable itself after short period of inactivity. All these settings can be set up in the abovementioned pkl.ini file and individual layouts settings.
Of course, you can make your own layouts for any language, including the keyboard help images for various modes, using free tools. Note that PKL is, essentially, a compiled AutoHotKey script, and its source is available for download (including all needed tools to create your own layouts), so if you want to change or improve something - you are welcome! Don't forget to visit the official forum if you need some question answered or have some suggestion.