There's a bit of confusion out there on the net about this file, but it is more likely a part of Zone Alarm firewall that is misbehaving. See here: http://www.neuber.com/taskmanager/process/vsmon.exe.html
I've heard lately that the latest version of ZA conflicts with other security software, especially Norton antivirus. In order to get a clearer picture of what may be happening on your system, we need a bit more information.
1. What security software are you running? Mostly what antivirus and firewall?
2. What version are you running? This may be a known problem with an older version of Zone Alarm.
3. What operating system? Please confirm if you are running XP and if so do you have SP2 installed and that you have all patches up to date.
A malicious file can be named anything and they often take on names of legitimate programs. Checking a file's properties is a good idea but it still leaves some questions to my mind, so to be extra sure, upload the file at jotti
and post back the results if anything suspicious is found: http://virusscan.jotti.org/
That site is very busy at times, so if need be you can try another similar service: http://www.virustotal.com/en/indexf.html