I'm making a python script that should run in the background and notify a user of changes, and I'd quite like it to work cross-platform. Main problem is, I don't have access to a mac at all, so coding specifically for it could be very difficult. wxPython seems like massive overkill for simple popups, so is there anything with a lighter footprint?
Adobe Wave is a cross-platform notification framework however I have not used it and I do not believe it is a desktop-oriented deal, but rather something for rich Internet Apps and plugging into web sites. Still, it's some sort of cross-platform notification so possibly worth a look-see.
That reminds me, you may be able to find an AIR notification system out there that you could somehow trigger from Python. Mono with GTK# comes to mind as it supports the three major desktop platforms. See this GtkSharpNotification example perhaps.
Finally, for my third strike, maybe a cross-platform GUI toolkit like wxWidgets has the widget you need.
Does Python on Windows and Mac also ship with Tk wrappers? If so, you might be able to roll your own notification box. I do not think they have a dead-simple notification API (i.e. you pass it a string and a cute box pops up for 5 seconds) however at least you will only have one codebase to maintain.
I am thinking about other cross-platform apps such as Skype, Dropbox, and Thunderbird. Skype and Thunderbird seem to have rolled their own, and Dropbox went the platform-specific route.