I've been using my capswarning extension for Firefox for months and months on all my computers, and it was time to a) say it's final b) update it for Firefox 2.0. This is now done and you can download it from Disruptive Innovations as always : windows version and linux version. Should be soon available from this link at add-ons.mozilla.org too.

Capswarning adds a very visible warning label to all password prompt dialogs if the CAPS-LOCK key is on. Very useful to avoid mistakes in passwords.

caps-lock warning