Paymo.biz Time Tracker is a Firefox add-on plugin that helps with tracking your time using the paymo.biz API.
Before using this plugin, you'll need to set your API key, username and password in plugin's Options.
This plugin adds a small statusbar icon. You can track your time using the popup menus you can access by left/right clicking on it.
You can install the add-on from the Mozilla Add-ons: Paymo Time Tracker