This site has instructions showing you how to switch your keyboard to
an Icelandic layout.

http://www.mentalcode.com/nl/islenska/kbd.page?return=%2Fnl%2Fislenska%
2Findex.page%23kbd

Extra tip: If you're using Windows and you see posts with garbled
characters on the Yahoo Groups website, you can usually remedy that,
by going to the View menu > Encoding, and changing between Western
European (Windows) or Unicode (UTF-8).