PI4TH2 club station at University of Twenthe, The Netherlands  excellent; several ham-band SDR (Software Defined Radio) receivers

PA3AGN, The Netherlands multiple receivers, 10 kHz - 1300 MHz, with links to other receiver sites

GlobalTuners remotely controlled radio receivers from all over the world

DX Tuners - global network of remotely controlled shortwave and VHF/UHF receivers

S-Meter Net  multiple receivers worldwide

The DXZone worldwide HF and VHF on-line receivers

Shortwave radio - Virginia, USA (1 - 30 MHz)

Java Radio - near Stockholm, Sweden (100 kHz - 1300 MHz)

Visual Radio, Germany (1 MHz  - 2 GHZ) only works in an ActiveX compliant browser

N2JEU's 2 Receivers - Upstate NY (500 kHz - 30 MHz)

QTH Wellington/New Zealand (0-30 MHz) 2 receivers

Remote-control ham radio transmitter/receiver

"Remote Hams" receivers

QsoNet  access ham radio transceivers via internet

Here is a list of web-controlled radio receivers