Honest, I'm not getting at you Paracab, but it's sort of amazing that there are still plenty of people around who are quite happy to open attachments blindly.
These days this is the way most worms and virus get onto folks systems and the dangers of opening unknown attachments has been so widely publicised that one would think that almost everyone was aware of it.
But you're in "good" company - a recent survey of office workers
http://www.theregister.co.uk/content/55/35393.html showed that 2/3 "are not aware of even the most basic virus prevention measures".
BOAC's advice "...click on the attatchment, select 'save to disk', and run it through my virus checker BEFORE opening" is sound.
Attachments with the .com - .exe - .pif - .bat - .scr suffix are always viruses unless you're actually expecting them. Attachments with the .gif - .jpg - .jpeg - .txt - .doc - .pdf may be safer, but virus writers often disguise a viral executable by giving it a double extension, ie readme.txt.exe - by default Windows suppresses the .exe part so that the reader sees it as just readme.txt opens it and baboooom!
Despite having a hardware firewall and good AV protection I just junk anything that doesn't look totally kosher without investigating further. Suggest you do likewise. Virus writers rely on "social engineering" techniques to make things look interesting and persuade you to open them out of curiousity - and curiousity kills more than cats....