It's currently being Slashdotted, but these guys have reverse engineered the old QuantumLink service, and have their own Q-Link server up.
They're offering a modified version of VICE so you can map an RS-232 port to a particular IP address so you can log in via emulation, or if you're feeling feisty, you can hack up some hardware to connect via a real machine.
This is excellent. I never got a chance to experience Q-Link back in the day, but I always dreamed of it. ;)
Check it out: