Does Linux have something like msconfig or services?

I want to disable unneeded services and programs that
may be running in the background. I also dont want them
to start up after rebooting.

Also, how can I know what I truly need running from what
is not safe to disable?

Thank you

having programs you dont need running at startup is more of a windows problem, i dont think linux really suffers from it...

have a look at the scripts in /etc/rc.d/
especially rc.local
these are the scripts which run dureing boot-up

but the best advice i can give, is if you dont need a program, un-install it.
you can get a list of running porgrams with the command
top

have a look at ownership of each thread, if its running as root, dont touch it !
look at the ones owned by you the user, there should only be running very few programs, all of them hopefully what you executed yourself.

(except maybe X, and a windows manager if your default is runlevel 3, but u need these anyway)

My Red Hat 8 system has a menu item in the main panel menu, from the little red hat, and it's at Server Settings/Services. That pops up a gui interface to start/stop/restart services. I think SuSE has a similar app, but I don't yet know what it is. I've just re-installed SuSE 8.2 Pro and I'm at the package update part of the initial install after CD 4.

try Yast2

I don't know what services the SUSE will enable by default, but you will want to turn off services that you don't use that could pose a security problem. The FTP service is one. You may even want to disable the ping service. (Actually, in linux/Unix they are called daemons rather than services)

If you look in /etc/rc.d/rc3.d
for run level 3 ie text mode usualy or /rc5.d for run level 5 gui.
You will see files such as S91smb. That one starts samba. If you dont want samba you can change it to K91smb.
Thats how it works "under the bonnet" the tools provided by Red hat etc
supply a nice interface for you to do this.
For info /etc/rc.d/init.d has the scripts to start the services (demons).

Is there a GUI for SuSE 9.0 Pro to do this? KDE, Gnome?

go to control center in kde you'll see YaST2 modules

Yes actually there is. Im running suse 9.0 as well and Im not sure if you have to install extra packages but if you go to the System--->Service Configuration menu there should be some programs to edit the services.