Especially if you use WindowsXP, verify the date of the last update in Task Scheduler, as some AV software doesn't update properly until you add a username and password to the task. By 4PM EST yesterday all AV vendors had updated definitions that identified MyDoom aka MiMail.R and any update since then protects you if you accidentally run the attachment.

Not that antivirus is needed to prevent this virus from spreading since you know not to open attachments you aren't expecting, even when they are purported to be from people you know, right? And even if you opened the attached *.zip, you knew not to run the *.exe, *.pif or *.scr in the zip, right?

Using the antivirus software's email scanning feature isn't necessary, since you can easily identify infected messages and delete them yourself. Antispam programs such as mailwasher (www.mailwasher.net) can be configured to remove many of the infected messages before they get to your Inbox.