According to Section 20 of the Law on Electronic Communication (adopted 8 December 2004, in effect since 1 January 2005): "The Minister of Economic Affairs and Communications has the right, in accordance with the purposes of use of radio frequencies, to determine the possibility to use radio frequencies without a frequency authorisation..." In 2008 the work of Estonia's National Communications Board, the Railway Inspectorate and the Technical Inspectorate were consolidated in the newly created Estonian Technical Surveillance Authority.
"Conditions for use of radio frequencies and technical requirements for radio equipment exempted from frequency authorisation," Minister of Economic Affairs and Communications Regulation No. 35 of 13 April 2006, in English. Updates and replaces numerous separate regulations for specific technologies (CB, PMR446, wireless microphones, etc.) as well as nonspecific short range devices. In Estonian, the title is "Raadiosageduste kasutamise tingimused kindlaksmääratud raadiosagedustelning tehnilisest loast vabastatud raadiosaateseadmete" - published in the official gazette, RTL 35:613 (24 April 2006).
Wifi.ee in Estonian and English. This site has a searchable-clickable map showing how much of Estonia is now covered by hotspots and how many there are in each district.
The world's first transnational bus service with free WiFi has started between Tallinn, Estonia, and Riga, Latvia: "Wi-Fi Bus Crosses the Border" by Cyrus Farivar, Wired News, (6 March 2007)
"IT News" in Estonian Economy, April 2003: "...6.8 percent of all wireless Internet areas in Europe are located in Estonia, although 1.4 million Estonians make up only 0.2 percent of the continent's population..." This short article has many other Estonian wireless Internet statistics.
"Cyber Attack Vexes Estonia, Poses Debate," by Christopher Rhoads, Wall Street Journal, 18 May 2007, page A6: "A cyber attack on the Baltic country of Estonia will likely shape a debate inside many governments over how such attacks should be considered in the context of international law and what sort of response is appropriate. The Estonian government compares the episode, which it has blamed on Russia, to an act of war... The attack began on April 27, shortly after Estonia removed a Soviet statue from downtown Talinn that commemorated Red Army soldiers killed by the Nazis in World War II. The incident inflamed relations between the two countries... In the early days of the attack, government Web sites that normally receive around 1,000 visits a day were receiving 2,000 visits every second, according to [Madis Mikko, a spokesman for the Estonian defense ministry]... Estonia is particularly vulnerable to such an attack because of its heavy use of the Internet..."
"Estonia Presses Bush for Cyber-Attack Research Center," by John D. McKinnon, Wall Street Journal's Washington Wire, 25 June 2007: "President Bush and Estonian leader Toomas Hendrik Ilves talked over the possibility of a new NATO research center - in Estonia - to focus on cyber attacks like the one that crippled the Baltic republic in April... [Bush] thanked Ilves for his idea for a NATO center to be located in Estonia that would study the issue. NATO sent an observer to Estonia to monitor its attack, but NATO was designed to counter physical threats and hasn't yet developed detailed plans for cyber warfare."
"The government on 14 August [2001] issued a decree, which bans commercial Internet service at the radio frequency of 2.4 GHz from 2003, ETA reported. The decision will result in at least 20,000 computers in rural areas losing convenient low-cost access to the Internet. Noting that the use of this frequency is free in all other countries, the service providers of the radio link are protesting the government's action..."---Baltic States Report, RFE/RL, 6 September 2001. We have not been able to corroborate this [now outdated] report...