[This is a previous posting from someone else, that I’ll later respond to]
Hi all just started using Ubuntu 9.10 today and to be honest it’s hard moving away from Windows but hey it’s going well apart from finding anti-malware, anti-virus and firewalls online that can be installed could someone in very basic terms (as i’m not great with pc’s) tell me how i can get them please.
This is a real operating system, Linux is not Windows! You don’t need to worry (certainly at the moment) about viruses and spyware! 
This is ‘one’ of the reasons why people use Linux.
Unless you are using your box as a server, you “probably” don’t need to worry about a firewall either if you are set up correctly. If you are in an office, then the office router should take care of this for you, if you are at home then you should be sat behind a NAT router, which on it’s default settings should do everything you want with regards to home firewalling.
If you are using a “modem” (rather than a router) , throw it in the bin immediately and get a router. I’ve been using Thomson Speedtouch 546’s for years (10?) at £23 a throw, they work well. and are relatively inexpensive for the job they do. (it will also make your connection AND PC quicker as it offloads a lot of work from your PC’s CPU)
If you want to spend some more money for something a little prettier, I’ve just got a Belkin N1 vision which seems to work very well and includes wireless connectivity. (albeit a it’s little more expensive)
If you want to “play”, take a look at “firestarter” for a GUI based firewalling tool, or for a “proper” server based setup take a look at “firehol”.
How to tell if you have a modem or a router:
If the connection from your ADSL device to your computer is “USB”, rather than “RJ45” then either you have it plugged in “wrong” or it’s a modem.
Further Information:
http://linuxmafia.com/~rick/faq/index.php?page=virus
and
http://www.techthrob.com/2009/03/02/do-i-need-an-antivirus-program-on-linux/