i've been working on some stuff that will allow you to create a dedicated shoutbox window with another user. it makes it easier to talk to a specific person if you get bombarded with shouts from various people at the same time.
you can open it by clicking on the 'horn' icon next to the SHOUT label in any members tooltip. when you click that horn, it'll open up another window with a shoutbox to that person only.
feel free to play around with it, once i work the bugs out of it i'll put it in a more obvious location... but for now it's sort of hidden. :-)
if you have any problems with it, please post a comment on this blog... thanks!