Thanks, nice story.
My reaction was somewhat opposite to what the others described: I thought the beginning was a somewhat generic and implausible brand of superintelligence porn, but the end was cool. Mostly I enjoyed the way a "conversation" and battle between superintelligences was depicted, and the attacks and countermeasures were rather cool.
http://www.infinityplus.co.uk/stories/under.htm?2. 15-30 min read time, rated "pretty good" by me.
There are a couple of interesting features of this story that I would like to discuss - but I don't want to introduce any spoilers, so I'll just leave this here for now.