A lot of you probably already know about this, but if you ever want to do multiple file uploads in Firefox then this Firefox Add On / Extension is for you:
This Add-On lets you drag a bunch of files from your computer and drop them on a standard file input upload box. If the web site has been built a particular way to allow for multiple upload boxes generated dynamically (such as Gmail), dragging a bunch of files onto the single upload box will automatically generate a whole heap of individual upload boxes. Very neat! :)
This is mega handy when you want to send a whole bunch of pictures to someone via Gmail.