How do I reformat status messages? I'm trying to restyle the status messages block, and I just can't figure out how to do it.  I ought to be able to -- it's just defining a theme function, right? :) -- but it's just not happening for me.  I'm not sure if I'm not defining the function properly, or not registering it properly in hook_theme, or even if I need to register it in hook_theme.  Arggh -- can anybody out there clarify this for me?  Thanks very much!
the function you need to hook is:

themename_status_messages()

where themenameis your theme's name. You can see the status message theme docs here.

What specifically are you trying to restyle? Most of it can be done with CSS, without introducing a theme hook.