1. Yes - there's a script for battery-status monitor that makes a small bubble come up giving you the percentage of battery. You can assign the script to either button(s) using the Input Actions on Control Center and/or you can create a menu item for it using Menu Editor and/or you can create a desktop shorcut for it by first creating the menu item and then dragging and droping it to the desktop or placing the icon in your task bar. I personally have the script assigned to Ctrl+B.

2. You can launch almost any Maemo app from xterm once you've determined what the command to launch from xterm is - then you can do the same things as I mentioned in #1 for launching.

If you don't want to add an icon to your KMenu first but still want to add the app to the desktop or task bar then do the following:

To specifically set up a desktop short cut: Open Konquerer -> /home/user/desktop -> Menu -> Edit -> Create New -> Link to application -> Tap on the icon to select an icon; give it a name - > Tap on the Application Tab and type in the Command that you used in Xterm to launch the application (eg: for XMMS it's simply xmms or for FOTAQ in scummVM it's usr/games/scummvm -f queen).

You can also set up a shortcut link to the system tray by doing a very similar set of steps: System tray menu -> panel menu ->Add Applet to Panel -> non-KDE application launcher -> fill in the blanks using the same method as above except here you type the xterm command in the Executable space.

3. Don't know about using the Maemo IM clients I personally use Kopete (KDE Jabber client) - I prefer it over the maemo clients anyways. Sorry can't be of more help here.

4. No I think it's just you - I don't notice any difference at all in the brightness of the screen. The only thing I can think of is that perhaps your color scheme is making things look more dim? Like maybe the background isn't set to WHITE but to an OFF-WHITE or something. To check this go to Control Center -> Appearance -> Colors.