How do I type extra fonts in Ubuntu 10.4?

texlive doesn’t have much to do with the fonts you use when you type messages at Facebook. If you ever decide to try your hands on LaTeX, you should install that, but if you don’t know what LaTeX is, don’t bother :)

How to use the fonts differs per application. You can set the font used on the desktop with the Appearance prefences window. In Firefox you set it in Edit->Preferences, then under Content you can set the font. I believe the default font should support most typing systems, but if it doesn’t, you can try to use the font “Ubuntu” which should really support a lot of systems.

@vincent hey, mate. good to meet you again. I can’t find the “ubuntu” font in the selection list.

Use gucharmap at Applications->Accessories->Character Map.
Also, what you are talking about are called character tables rather than fonts. Gucharmap handles both.
If you just want to insert an arbitrary Unicode character and you already know its code point, you can just type Ctrl-Shift-u and then the number ☺

Yeah, still here infrequently…

Oh wait, 10.04, I’m not sure whether the Ubuntu font was already present then. You can download it manually.

If you need to insert individual characters, you can use Character Map indeed. If you want to be able to switch keyboard layouts (to make characters you use more often) you can configure it in they Keyboard preferences window under the Layouts tab. I believe that if you add a second keyboard layout, that a switcher will appear in the panel that allows you to alternate between the two with the click of a button.

GREAT! found that it works.. cheers @Vincentt . But I also found that I can only apply four layouts (currently I have three by country and one by language)..

@Anatelostaxus After playing around with it a bit, I’ve duplicated that issue of only having 4 layouts available at a time. I’m not sure why this is the case, I’m still looking into it. Of course, it’s pretty easy to remove one or more layouts, but I understand it’s probably a pain to have to do that if you need to change frequently.

Apparently this is a limit unfortunately hard-coded into X.org. For reference, see this askubuntu post and this freedesktop bug report. It may be fixed in some later version, but it is likely to be some time before this happens as xkb is a low-level protocol.
If you have C programming skills or know someone who does, you can of course try to fix it yourself and possibly gain international fame for doing so!