The Internal Revenue Service has offered a glimpse of some of the changes being made to the draft instructions for the new Form 990 — and says it will post the revised instructions in full on the its Web site by August 15.

The Form 990, which was completely redesigned for the 2008 tax year, is the primary document that charities annually file with the federal government.

Among the changes to the instructions will be a revised definition of the term “key employee” for the purposes of reporting executive compensation, transactions with charity insiders, and other items.

In response to criticism that the original definition was overly broad, the IRS has laid out a three-prong test to identify key employees.

To counter complaints about some of the new form’s extensive reporting requirements, the revised instructions will lay out how charities can prove they have made a reasonable effort to obtain relevant information about the family and business relationships among their trustees, officers, and key employees.

Changes in instructions were also made to the supporting schedule that hospitals must fill out and to the schedule requiring information about tax-exempt bonds.

The revised instructions are based on public comments the IRS received following the April release of its draft instructions.

An update on the IRS Web site says that the upcoming release of the amended instructions will be accompanied by background documents intended to explain the changes.