Proxies (Best?)

I hope this is the right place to post this. If not, would an administrator please move it? Thanks.

I've got a situation where we are using iPlanet proxy server to allow some of our web browsers to ONLY go to certain sites on an "approved" list. If they try to go to sites that aren't on the list, they get a message stating that they are at a limited workstation. This would be great overall if the iPlanet proxy (running on Win2K) wasn't so flakey. The performance seems poor because our clients complain about pages not loading completely or at all at times. I've been looking at Freshmeat.net for a decent open source/free software replacement. But there are quite a few proxies and they all seem to have different focuses.

What I need is just an HTTP proxy that will allow me to maintain a list of approved sites. Ideally, it should have a web interface for managing the approved sites since I'm not really the maintainer, a non-technical person is. And finally, the list should work with regular expressions so that wildcards can be used to allow people access to subparts of the approved sites. If possible, we really DON'T want stuff caching on disk because we can't afford to be legally viewed as a "content provider". Since the definition of that is pretty nebulous it makes the non-caching feature pretty important. Anyone know of anything like that?

I use Squid w/WebMin:

http://www.squid-cache.org/

there is a nice web based interface for Squid with WebMin:

Squid, however, uses disk & memory caches. Not sure if it can be configured for only memory cache. Maybe. Let us know, Thanks!