We would want something like we do for Live Preview for wiki syntax, but for the PDF generated from LaTex.
Dirk already has a png preview from the generated PDF (with ImageMagick)
PediaPress has a very nice interface
If we use Wikipublisher, we could add this preview image in a separate pop-up window, which refreshes to the same page. (on demand)
http://simile-widgets.org/runway Page browsing
Maybe we can find some live preview of Latex output without the PDF...