Greetings:
Questions:

1.Where to locate the services in linux --- just like in windows so that I can stop or start the services installed.
2.The equivalent of Ctrl+Alt+Del in suse
3.In windows firewall you can add port or exceptions---in suse 9.3 how to achieve this.
4.What is the best firewall and antivirus/spam available for suse linux.

In /usr/share/doc/manual, you have two SuSE guides: the administrators and users guides.

1) from the main menu, Control Panel - YaST2 modules will get you to various services.

2) ctrl+alt+del in suse same as in windows. rarely needed. use ctrl+alt+backspace instead (restarts the X server instead of rebooting).

3) see 1) above.

4) don't know what would be the *best* for suse, but suse comes with its own firewall application. go to main menu Control Panel - YaST2 modules - Software - Install and remove. click Administrator Mode and provide root password. from the search dropdown list box, select Package Groups. look through the lists for firewall and antivirus apps in the software which in on installation media.

"1.Where to locate the services in linux --- just like in windows so that I can stop or start the services installed."

ans: do you mean the those auto run program while boot up Suse. if yes, you can control them by the following command:
# chkconfig --list
# chkconfig --add apache2
# chkconfig --del apache2


2.The equivalent of Ctrl+Alt+Del in suse

ans: same as Windows, details at /etc/inittab


3.In windows firewall you can add port or exceptions---in suse 9.3 how to achieve this.

ans: better use YAST --> Security & Users --> Firewall


4.What is the best firewall and antivirus/spam available for suse linux

ans: Suse come with SuSEfirewall2. your can use clamav for antivirs and amavisd for spam