I just started a logic class, and I need to be able to type unicode characters as used in symbolic logic (such as the Omega sign) that do not exist on a standard US-101 keyboard.

After a bit of googling, I found that Gnome supports Control+Shift+U then the code to type unicode. KDE doesn't directly support this. However, KDE does support the SCIM input method, via the skim package.

I installed this (sudo apt-get install skim, ain't it lovely?) and used the shortcut key control+space (as setup in the dialog), expecting a window, a textbox, something -- anything -- to happen on the screen. Nothing happened, and my keyboard continued to function as normal.

So far, I'm less than impressed with the documentation available. I've gone through everything, and as far as I can tell, I've done everything correctly.

Does anyone know where one might learn how to use Skim? (the SCIM wiki has effectively nothing useful as far as I can tell, and google revealed the existence of SCIM, but not much on how to use it, at least, no introductions to the concepts, and no direct explanations of the system, just the very vague and generic "SCIM is an input method platform")

Last time I used skim (I use scim mostly), I had to tell KDE the existence of another input method:

export QT_IM_MODULE=scim

and in .kde in Autostart "skim -d".

And as far as I remember it skim is just kind of a frontend to scim, so you may possibly have to install scim anyway.

And the Gtk/Pango input method with Ctrl-Shift-u<code point> seems to be on the KDE 4 wishlist.

It btw. doesn't depend on Gnome in any way - if you use for example Xcfe's "terminal" (which is Gtk-based) and start a Unicode enabled vim inside, Ctrl-Shift-u<code point> will work. Same goes for Firefox, Gimp, gaim/pidgen and so on.