Blame Cheney First
The best strategy to bring the Bush-Cheney Administration to justice would be to impeach the more corrupt and less popular Vice President, Richard B. Cheney, first. This strategy may make it possible for Congress to obtain Bush's testimony without Cheney holding Bush's hand as he did in Bush's testimony to the 911 commission investigators.
The evidence of Cheney's involvement in crimes during his tenure as President of Halliburton (e.g. bribing Nigerian government officials and illegal business dealings with Libya and Iran) would make it possible to add perjury to Cheney's rap sheet and give Congress evidence of an impeachable crime – a la the Clinton impeachment.
There will be no need to attack Bush directly, he will become and instant lame duck when the charges against Cheney are publicized.
The website http://iran-conoco-affair.us contains information on how Cheney and his oil business cronies have worked to cover up their companies' illegal business dealings with Iran.