Someone asked if GNOME does inline spell checking (like so many other desktops, including KDE and MacOSX), where words are underlined in red if they aren't recognised.

The answer is yes, some GTK applications do this, but you may need to enable it in the application concerned.

Less obvious at the user interface level, but entirely logical, is you need the corresponding aspell dictionary installed. In my case the missing command was;

apt-get install aspell-en

and restarting the application of interest (GAIM) shows not only can I not spell, but I can't type either. But I guess anyone still reading my blog knows that already.