Skype

For the general public

Install

On an XO-1 or XO-1.5 with OLPC OS 10.1.3:

switch to GNOME,
connect to the Internet,
using Firefox, go to the Skype Web site and download the Linux Static version (here's a direct link),
locate the file using the File Browser — it is most likely in the "Download" folder in your home directory, with a file name like "skype_static-2.2.0.25.tar.bz2",
right-click on the file and choose "Extract Here",
wait for the archive to extract to a new folder — it should look like "skype_static-2.2.0.25",
open the new folder, you should see a file called "skype" — double-click it.

Not yet available, check with Skype for latest news or devel list discussion.

Audio does not work immediately. Adjust the options to make the microphone work:

click the tiny Skype button in the bottom-left of the main Skype window, choose "Options", and in the list of categories on the left, click on "Sound Devices",
on the right, click the drop-down box next to "Microphone" and select "HDA VIA VT82xx, CONEXANT Analog (hw:0,0)" for XO-1.5, and "CS5535 Audio (hw:Audio,0)" for XO-1,
click "Apply" at the bottom,
test the setting with the "Make a test call" option.

On an XO-1.5, video should work immediately. To test, go to "Video Devices" and click the "Test" button in the black box.