Our client at work reported that some javascript is not working on IE but it was working on firefox. I was at the edge of taking my whole dev environment back to windows on my dual boot windows/Ubuntu machine but IEs4Linux saved my life!
Installing it was not that easy because i almost tried installation 10 times and it was failing due to gtk, file not found,... errors. I also needed to manually download many files from microsoft and put them in its download directory (/home/reza/.ies4linux/downloads/ie6/EN-US) but finally it worked like a charm.
see this : http://ph.ubuntuforums.com/showthread.php?t=752865