well there are a lot of programs on the market for that...none are cheap but most are effective (anything claiming to be free is trash in this department)
i use SpectorSoft 360 CNE
and it's really effective, you can get screenshots and logs of every activity, export video all kinds of fun sneaky stuff. again, not cheap, but really effective. they've got different levels as well depending on the size of your install etc..
as a note of caution, before you install ANY OF THIS stuff or purchase it or anything. you need to get with your H.R. department (if you have one) or the owner of the company and make sure that it's communicated CLEARLY to your employees that the company reserves the right to monitor computer usage in any way you see fit, and that you reserve the right to take corrective action based on these investigations. it also needs to be in your company policy. they don't have to be told what you're using to monitor, or how often you monitor, they just have to be told that you "can" and "might" monitor their usage...if you don't communicate this, then you won't have any ground to stand on if you get sued
Edited by dsenette, 02 March 2010 - 08:13 AM.