I don't know of an easy (pre-built) way - but shouldn't be too tricky using pages.xml navigation rules...
Sounds interesting, could you elaborate? I thought most rules there were for post-action navigation.
It might be a nice "you-can't-do-this-with-plain-JSF"-addition the manual since I would think this requirement is quite common.
I'm bumping this since Pete seems to be up and running once more ;-)
I suppose I was thinking about doing this on another view, rather than a popup from the current view.
For a popup (probably a better idea) you probably could use a modal panel from richfaces. Ask over there are you would need to get the sequencing correct calling the actions... and post a trackback here.