The EU has set a date in early June for Microsoft's antitrust hearing regarding the software manufacturer's practice of bundling its Internet Explorer (IE) web browser with Windows.

Jonathan Todd, spokesman for the EU's Competition Commission, said the agency had set June 3 to 5 for Microsoft to respond to charges that it 'shields' IE from competition.

Sources close to Microsoft, however, said that while the company has requested the hearing - a procedural matter that was required when it submitted its written response last week - it has not made a final decision about whether it will actually go through with the conference.

The hearing would be Microsoft's chance to answer EU charges that it "distorts competition" in the browser market by including IE with Windows. The "tying", as the commission put it, gives IE "an artificial distribution advantage which other web browsers are unable to match."

The accusations stem from a December 2007 complaint by Opera Software, the Oslo-based development firm whose Opera browser currently accounts for less than 1 percent of the web browser market. At the time, Opera said IE "harmed the web" and demanded Microsoft unbundle the browser and adhere to web standards.

Since January, several chief browser rivals, including Mozilla and Google, which make Firefox and Chrome, respectively, have joined the case as third-party participants.

Three weeks ago, a trade group that includes other competitors, among them Adobe, IBM and Oracle, were also given access to the allegations. Companies that have been granted third-party status will be allowed to participate in the June hearing.

Although the commission has not specified what it might require of Microsoft, it has hinted it could fine the company, force it to allow users to choose alternate browsers or require it to disable IE.

Microsoft has added a 'kill switch' of sorts to Windows 7 that will let users prevent IE8 from running. Opera's CEO, however, has said that he considers Microsoft's move to be insufficient. The company's Windows 7 Release Candidate (RC), which launched publicly today, is the first chance most users have of testing that kill switch.

The case could go on for years after the hearing. In an earlier antitrust action, in which the EU charged Microsoft with blocking competitors' access to technical information they needed to make their software work smoothly with Windows, Microsoft defended itself at a November 2003 hearing. The case was finally settled in October 2007, after Microsoft lost a critical appeal and acknowledged it would comply with the EU's demands.

According to web metrics firm Net Applications, IE accounted for 66.1 percent of the browser market in April, down 0.72 percent from the previous month.