THUS.SPAKE.Z  I, also, have the issue of my MacBook Pro's temps sometimes shooting up and fans spinning at over 5000 rpm when "Protect My Mac" is on.

When checking Activity Monitor, I find that iavd is at nearly 100%. Turning "Protect My Mac" off brings temps back down and fans back to idle speed (2000 rpm).

Hope the developers find a fix for this issue.

Other than this one problem, iAntivirus seems to work ok and is fast. It hasn't found any viruses, yet, but that's because there aren't any active ones in the wild at this time, but I do like to keep an anti virus program available and run it once in a while.  
(Version 1.3.6)

TRANCE  works great on 10.6.1, scans literally 10x faster than macscan and actually found the trojans that were giving me problems unlike macscan which found nothing  
(Version 1.3.6)

RAGTAG  I installed iAntivirus a few days ago, and started having problems with my Belkin USB Network control center software. I kept getting a message regarding "sxuptp driver has not been installed." After some searching I discovered this error was somehow connected with i

Antivirus. After uninstalling it I have had no further issues with sxuptp driver messages.

Rag  
(Version 1.3.6)

IGREG  The new iAntiVirus by PC Tools continues to work nicely with background scanning (and no apparent slowing of the system), easy interface, fast updates and there is a free version. The weaknesses of ClamX AV are its fairly complex interface, weakness in providing much automatic protection. Although ClamX AV is also free.

I have always used an antivirus, not because it is really needed at this time, but to be familiar & comfortable using an antivirus if & when it is really needed.

Norton AV and Intego AV are both good, and while the purchase prices are not too bad, the annual virus definitions subscriptions are way too expensive.   
(Version 1.3.6)

IGREG  I have to say that my review may have been hasty, it seems to use a lot of CPU at certain times. I am looking into it  
(Version 1.3.5)

VICJOE  The lengthy list of viruses/malware on the developer's page is misleading; there are a number of old viruses for OS 9 and the Classic environment, yet this software only works on Intel machines with Leopard, which of course cannot run the Classic environment.  
(Version 1.3.5)

IGREG  Have had it installed for several hours now. I have noticed no problems. Uses about 40 MB of RAM for application and a background program. Quick scan was pretty quick. Even the full scan was not too bad, about 45 min for hard drive with about 55 GB of data. No noticeable system impact. Interface is user friendly. It is free for home users.

I switched from Intego Virusbarrier, which uses more than twice the RAM and has a weird and confusing interface with the current version. Plus its annual subscription renewal is expensive.  
(Version 1.3.5)

SURFSPIRIT  BAD! OK, it was lot faster than ClamXav to scan files, but din't found any of the two virus ClamXav had made alert, I also run Kaspersky via Parallels to the same usb pen, and Kaspersky confirmed the two virus. All the antivirus used their most recente database. ClamXav seems better, you can even easy scan any file or folder by mouse click menus. I also run Sophos aclamed anti virus and the result was the same as iAntiVirus, a shame! Above of all this, I am completely sure my pen was infected because it was used to try to desinfect a friends pc that was full of virus and malware. So if you want an anti Virus for mac so you minimize your friends pcs nightmares, choose ClamXav!  
(Version 1.3.5)

RORO01  STILL THE SAME PROBLEM

"Installation failed. The installer could not install some files in "/". please contact ..." - iMac Intel 10.5.6  
(Version 1.3.5)

RORO01  Installation failed

The installer could not install some files in "/." iMac Intel 10.5.6  
(Version 1.3.4)