Yes, you can read in landscape mode. You have a continuous mode on the iLiad, which lets you flip through the pages by using the flipbar and displaying a screenful of page after the other (almost like reading one half page after the other)
Reading like this is almost 1:1 size with A4 pages. Very comfortable to read. If you read scientific papers with colums, you should check out the multi column viewer, made by wpd
http://forum.irexnet.com/viewtopic.php?t=1953