Hello,
Not all PPC programs will run on Rosetta, but most will.
Virtual PC is the only program I know of right off, that will not run on Intel Mac's. But, it's not needed as they can run Windows without Virtual PC.
Also, any program that installs a control / icon in the Preference Panel is supposed to fail as well.
Maybe someone can comement on one, but as far as
I know none of the virus programs have gone
Universal and work correctly on a Intel Mac.
Norton Antivirus is Universal.
http://service1.symantec.com/SUPPORT/num.nsf/docid/2006012013550811?OpenDocument &src=hot∏=Norton%20AntiVirus%20for%20Macintosh&ver=10.0&csm=no&seg=hho&tpre=
I prefer the free ClamXav.
But, ClamXav is not as novice friendly as people are accustomed to. It is better as a limited scanner.
It's e-mail integration is not as friendly, and can be quite damaging if you make a mistake.
But, it's manual scanner, and folder watching scanner are great.
I have it set to monitor everything I download to my desktop.
With the reported problems, and less than friendly e-mail integration, I would not use it to scan incoming e-mail.
For a free antivirus program, ClamXav is great. But, for those who want the ability to just install and forget it, you'll be better off with a commercial program.
Many web-browser plug-ins are also not yet universal. So, you'll have to run Safari in PPC mode to use some plug-ins.
You can read about that at:
http://docs.info.apple.com/article.html?artnum=303059
You can read about running programs in PPC mode at:
http://docs.info.apple.com/article.html?artnum=303120
While not complete, you can see a list of Universal Applications at:
http://macintouch.com/imacintel/ubinaries.html
and:
http://www.versiontracker.com/macintel/
Hope this helps.