An angineer by the name of Alex Tomanovich produces many excellent spreadsheets for structural calculations. Many are available at the AISC website SteelTools.
There is a recent posting there for one of Alex's spreadsheets that covers IBC 2009 seismic. The 2009 IBC paralells ASCE 7-05. Although I have not tried this particuilar spreadsheet, I have used Alex's spreadsheet for IBC 2006 seismic. It is a top-tier worksheet.