My newest creation, Gmail Checker, has just been released. You can get it from the downloads page.
Gmail Checker is (yet another) Gmail notifier. It sits in your system tray and checks your Gmail account(s), notifying you when you have new mail. It supports multiple (unlimited) accounts, Gmail for your domain, is open source (source will be posted soon) and has many customizable options.
It is written in Python using wxPython, which means it runs under various operating systems, but I haven’t tested it on anything other than Windows. The current download link is a setup file that installs everything required to run it, which is why it’s a bit large (3ish MB), but you can also just get the source (50ish KB) and run it anywhere were Python and wxPython are installed.
Caveat emptor, ActiveState’s ActivePython for Windows doesn’t contain the SSL library necessary to run Gmail Checker, so you will not be able to run the source file it if you have ActivePython, unless you copy the files _ssl.lib and _ssl.pyd from the regular Python installation to the corresponding ActivePython directories. That’ll do the trick, or you can just use the full-blown setup that contains all necessary files.