Windogg, I'm with you!
Here are the things I've done to get my company "under controll".
First step was setting company policy on personal use of the internet and getting monitoring software and letting users know it was in place. All it took was a couple of embarrassing moments and people got the message.
Second was a memo from the president of the company stating that no employee shall forward ANY email attatchment that is not necessary for business... PERIOD. The first couple we caught we called on the carpet and that took care of that... ninty percent of the crap attatchments were INTRA-company.
Third, a memo (again, pushed through the President's office) saying that NO SOFTWARE, business or otherwise is to be loaded by anyone but the IT staff. To have software installed you must provide a written request (forms provided by us) as to the nature of the software and its business use. If it is not business related, they can send in a request and it will be reviewed... <<here's the kicker>>... if we allow them to have the non-business software, they sign a sheet saying that they understand that they are taking COMPLETE finacial liability for any/all damage done to the computer and/or operating system, to include the time and a half pay (only done on overtime) for a technician to troubleshoot and fix any problems and reimburse the company for any lost productivity hours due to the downtime of their individual workstation. Virtually NO ONE is willing to sign... so ultimatly, it is
they who don't want the personal software installed on their workstation.
Finally... a very good hardware firewall/web blocker/SMTP packet sniffer. With this, we can lock down the internent so that most non-business related sites are automatically blocked, others can be added at will and ones that need to be open (Apple.com was listed as "sports and leisure"

. This particular piece of equipment (WatchGuard Firewall II) also looks through email and attatchments. Things like the Annawhatshername.jpg.vbs are automatically stripped from email at the firewall and never even get a chance to be seen by antivirus software, but it can be set to strip whatever you want...so.... want to stop elfbowling... set it to strip it out!
Anyway... these things have helped me to reduce Help Desk stuff by about 30% and have reduced worktime websurfing by about 90%.
In answer to someone else's question, yes, I have all sorts of personal software on my machine... the President said that if it breaks, I fix it myself and since at any given time I've often got two or three machines which are my PERSONAL PROPERTY on site for testing stuff for the company, I've always got a backup machine to use "just in case" mine gets hosed. I've also got an admin password through the firewall, but as they say, rank has its priviledges!
Joe