Is there a way to install both: gnome & KDE desktops in openSUSE 11 (the way it is in Fedora Core 9 Linux, during install).
If not, can the second desktop (either gnome/KDE) be installed later after booting into opSUSE ?
Of course.
You can intstall both gnome and KDE desktop environment.
Please use YaST to install all of these packages
Both ways are possible, but let’s tackle through them 1 at a time:
During installation, select which desktop environment you want as your default, or which one will automatically load when you log into OpenSUSE 11.0, at the “Desktop Selection” section. Continue through the installation and you will come to a section called “Installation Overview” (check the left column for this heading). On this screen, you will see all of the hardware, settings, configurations and software that is about to be installed (since it is the last step before installation). Click on the “Change…” button and the software packages will load. Once they load, scroll down in the left column until you find the heading “Graphical Environments.” Once you get there, check the following 2 packages:
To install Gnome:
- GNOME Base System
- GNOME Desktop Environment
To install KDE3:
- KDE3 Base System
- KDE3 Desktop Environment
To install KDE4:
- KDE4 Base System
- KDE4 Desktop Environment
Once you have checked them, click “OK” and finish the installation.
The other method is after you have installed OpenSUSE 11.0. To do this, open YaST Package Manager, either by going into YaST (enter root password), go the “Software” section and then select “Software Management” or through the terminal by issuing the command: “su” (without quotes), enter the root password, and then issuing the command: “yast2 --install” (again, without quotes). Once you have YaST Package Manager open, the repositories will refresh. Once they finish, click the dropdown menu in the bottom-left of the window labeled: “Groups.” Select “Patterns” instead and wait for the left column to refresh. Now, scroll down in left menu until you find the heading “Graphical Environments,” select the following packages, and then press “Install All”:
To install Gnome:
- GNOME Base System
- GNOME Desktop Environment
To install KDE3:
- KDE3 Base System
- KDE3 Desktop Environment
To install KDE4:
- KDE4 Base System
- KDE4 Desktop Environment
Once that is done, press “Apply” in the bottom-right and wait for the installation to finish.
Switching Between Environments
Switching between desktop environments, say from Gnome to KDE, is very simple. Before you login, you will see a link in the bottom-left of the screen labeled: “Sessions.” Click this, and a prompt will appear. Select the desktop environment you want to boot into and then enter your username and password. Once you do this, you will be asked if you want to make this session the default session: this means that if you make this session the default (weather you selected Gnome or KDE), that desktop environment will automatically load when you login, rather than having to into the session prompt and selecting it.
If you set OpenSUSE 11.0 to automatically log you in when it boots, this option will not appear. To disable the auto-login, open YaST and enter the root password in the prompt. Find the heading: “Security and Users” (you can jump to this heading by clicking the link the left column with the name “Security and Users”). Once the window loads, you will see the users on your OpenSUSE system. Click the dropdown labeled “Expert Options” and select the “Login Settings.” In this new window, uncheck “Auto Login” (you can also uncheck “Passwordless Logins” if you want OpenSUSE 11.0 to prompt you for your password when you enter your username; this is suggested for security reasons, so if it is checked, it is suggested that you uncheck it) and then press the “OK” button. Now, click the “Finish” button in the bottom-right. Now, when you boot your OpenSUSE 11.0 system, you will be prompted to enter your username and password (if you unchecked “Passwordless Logins” in the Expert User option window [see middle of the paragraph]) and you can click the “Sessions” link to change your desktop environment.
Sorry for the length: trying to be extensive as possible. 
Thanks, in fact, appreciate your detailed reply :), as I am a beginner to Linux + openSUSE (pl see sig.)
PS:
Do you know of a decent book that has the basics + details, specifically for openSUSE 11.0?
Main idea behind Linux install for me is to try & understand Unix, bash shell & CLI.
(One edit: When you press the “Change…” button, select “Software” from that list)
Another edit: To change the auto-login option, open “User and Group Management” under the “Security and Users” section.
(Sorry, do to the length, I missed some errors in the post)
Wiley::OpenSUSE 11 and SUSE Linux Enterprise Server Bible
And here:
Novell Doc: OpenSUSE 11.0 - Table of Contents
If I’m not mistaken some of these documents are on the DVD too.