Has any one seen a reasonably simple to use and install firewall/anti-virus software..

The Linux kernel has one built in, I don't think it is configured, however. As for antivirus, there's no real benefit if you (need and) have one on your Windows machine.

The Linux-Firewall-part is called netfilter, the userspace-tools iptables. Probably both only need to be compiled. Why do you need a firewall?

Anti-Virus doesn't exist in this form. There are no "viruses" like in Windows. All AV-Scanners are Scanners for Windows-viruses with filesharing (Samba) or Mailsystems.

The real danger for linux are rootkits, and there are several rootkit scanners. In my opinion it wouldn't hurt to have one, normally they run once a day. If Meego get's large Meego phones could be in real danger because of their power. Spammers could send text messages, MMS, maybe they can even relay calls.

They could do more, the phone has a camera, it has a microphone, it has a gps, it has contacts and so on... not good for your privacy...

So how does a firewall help? It's not like it's broadcasting all your pictures on the lan.

Generaly i feel naked with out some form of control over the inbound & outbound traffic, ie: firewall.
It would also be nice to use it as a simple black\white list for phone calls & text messages..

An app to configure the firewall, and a kernel module if it isn't already built in, isn't outside the realm of possibility.

However, it would be of no use at all for controlling calls/text messages, as those come to the device via an entirely different route.

My replies to "Can Linux get a virus?" -thread cover a few points regarding the usefulness of malware scanner.

My reply in this thread has points about malware and firewall as well.

Then some points on physical security which IMO is by far the greatest infosec risk you will have with N900.

Summary for the lazy:

1. Unless you explicitly install and enable wrong kind of services firewall is useless.

2. Unless you do very stupid things malware scanner is useless (and if you do stupid things it will not save you from all the threats, so better to be smart).

3. If someone has physical access to your device while you're not watching they will be able to copy all your data (actual copying might happen on background OTA and if bandwidth is kept low enough you might not notice...)