squid is free and not only can you stop certain users from having internet access but those who do have access can be blocked from going to sites that can get you, your company or your network in trouble by using squid guard along with it. there's updates for the banned sites list almost daily and you can choose what catagories you want to block.
Bukhari:V3B48N826 “The Prophet said, ‘Isn’t the witness of a woman equal to half of that of a man?’ The women said, ‘Yes.’ He said, ‘This is because of the deficiency of a woman’s mind.’”
ISA server 2004. Cofniguration could be a bit problem for a newbie but if you can configure it properly believe me it will make your life easy. The best feature of 2004 which i personally like is that you don't need to install client on users system.
I used Wingate previosuly and believe me i had so much trouble in using it and daily had some problems with users complaining this and that.......
For monitoring use GFI webmonitor, it will give web based monitoring facilty, you can see what users are browsing, it will have a history you can also put restrictions on downloading and other features.
One machine can do the work of fifty ordinary men. No machine can do the work of one extraordinary man!