plugin for Quantum GIS which reports current bounding box and zooms to user-entered bounding box.
currently at 0.2, it works but is buggy.
the dialog box has an input field, a button to update map and a button to close.
the input field updates automatically to the bounding box of the map as you pan/zoom.
If you enter a bounding box into the input field and then click on update map the map pans/zooms to the specified bounding box.
The bounding box should be in the format:
minX,minY:maxX,maxY
that is, the x,y coordinates of the bottom-left corner, then the x,y coordinates of the top-right corner.