Jisho

http://blogs.yahoo.co.jp/kmr_tds/43541171.html

It seems that there is a place that's called いかなし with those kanji (in Ehime Prefecture), but いがらし appears to be a much more common reading. Also, Wikipedia lists two other readings: いからし and いそあらし. According to that entry, いがらし is when it's a family name, where as いからし is when it's a place name (except for the rare case of いかなし). The only example for いそあらし is a sumo wrestler's stage name.
http://ja.wikipedia.org/wiki/%E4%BA%94%E5%8D%81%E5%B5%90

I guess my point is that this entry isn't incorrect, since there actually is a place called いかなし (though there's no entry for いからし). However, it's pointing to the wrong Wikipedia article, which is why it has a different reading there. There probably shouldn't be an article linked to this one at all. Though, there isn't even actually a link to the article on this word's entry like there is with other words... Kind of useless.