The EchoVNC folks have released V1.36 of InstantVNC. Based on UltraVNC, it’s a VNC server that you can have those folks whose PCs you have to support download and install. Supposedly it gives you secure access to their machine without requiring them to (re)configure their firewall/proxy/whatever. I haven’t tried it yet myself but it sounds good and could fill a good-sized hole. Let me know if you have any experience with it and I’ll post a summary if enough of you ask for it.