I am also having this problem on my work PC, and it's rendered me incapable of having iTunes open at all while I'm trying to use the PC. Every 30 seconds, like clockwork, the iTunes window forces its way to the top of the Z-Order and makes itself the active window. It doesn't matter if there is anything happening or not, it does this even when idle.
I did notice that it was like the entire application was refreshing: if there was something being processed (such as download the album art for my collection), it would "start over" (e.g. it would go from 125/1850, refresh and then it's on 1/1725, so no progress gets lost.)
This system is running Vista Business. My home PC, which runs Vista Home Premium, does not experience this problem, nor does my coworker who is running XP SP2 and is running version 7.3.1.3.
Message was edited by: DeusInnomen (Clarified iTunes version number of XP SP2 system)