Now Firebug 1.9a3 available , compatible with Firefox 5 to Firefox 9(nightly).  if you want to know what issues fixed, follow this link.

Some highlights from this release.

• Autocompletion in Firebug Command line has been improved (issue 3622 and issue 4803)
• Vertical position (line number) is preserved across page reloads (issue 1413)

Also, Firebug Working Group has a new member: Stampolidis Anastasios (aka Tasos). Tasos has been long time Firebug contributor helping with issues in various areas and FWG is pleased to have him on board!