The IRS has published The Budget in Brief FY 2006.  Here is the opening:

The IRS budget request for FY 2006 is $10,679,261,000, a $443,174,088 increase, or 4.3%, over the FY 2005 enacted budget of $10,236,086,912. This represents a 1% decrease in Taxpayer Service and a 2% decrease in Business Systems Modernization, respectively, and an 8% increase in Enforcement. This budget request supports the IRS’ five-year strategic plan. This plan, which guides the agency’s operations from October 1, 2004, through September 30, 2009, underscores the IRS’ commitment to provide quality service to taxpayers and enforce America’s tax laws in a balanced manner. The three themes of the strategic plan guiding the future direction of the IRS are:

• Improve Taxpayer Service
• Enhance Enforcement of the Tax Law
• Modernize the IRS through its People, Processes, and Technology