Oxca makes a range of KVM products, including one to provide remote KVM access via TCP/IP. The latter uses a java applet and runs in the browser, and isn't very fine at all. The basic KVM is okay. It has the usual LEDs and buttons, and does the job. The remote KVM applet is a different story.
My smallest criticism is that because it uses capslock for commands, often capslock is enabled inside the KVM and disabled outside, or the other way around. That's irritating, but there's much that's worse.
The applet lacks essential functionality. There's no menu or button to select a particular port, no way to see which port you're connected to, and no way to see which ports are live.
It suffers from jumping button syndrome. The UI has five push buttons and one menu. The menu and four of the buttons move suddenly and unpredictably. I hate buttons that move just when I'm going to to click on them. (And I'm not happy about icons that look like my mouse cursor either.)
Even worse, it doesn't handle focus changes sensibly.
ctrl-f1 to change window, then later
to change back, and the host will think that ctrl is still pressed, so
if you now type
sudo foo the host will see
foo and stop responding to your commands and wild curses. Oops.
The manual is bad. For example, it does not mention how to
select a particular port. The manual is 99 pages long and does explain
how to burn CDs with Nero, but not
how to select a KVM port. The secret is to type e.g.
capslock 1 1 2 shift (thanks)
to change to port 12 and disable the host's screensaver, if any.
Update: The applet works much better over GRE and IPSEC tunnels than over SSH tunnels. Still not well, but much better.