Why hasnt the international war crimes tribunal tried Bush for the wars in Iraq & Afghanistan? Also how do you expect the conflicts to end?

What do you mean by the "international war crimes tribunal"? There is nothing by that name. Various tribunals have been set up to try people for war crimes, but that is done by the United Nations, and the US has a veto in the US. There is the International Criminal Court, but that can only try citizens of countries which have acceded to it, which the US has refused to do.

To answer more generally, might is still right, and the US has plenty of might.

"The World Tribunal on Iraq (WTI) is a people's court consisting of intellectuals, human rights campaigners and non-governmental organizations. It sprung from the anti-war movement and is modelled on the Russell Tribunal of the American movement against the Vietnam War. It counts among its supporters Indian Leftist author Arundhati Roy and United Nations Assistant General Secretary Denis Halliday, though consciously avoids a hierarchical structure. The WTI routinely finds that the coalition forces in Iraq are guilty of war crimes and violations of the Geneva Conventions. The Tribunal tends to receive less coverage in the United States and United Kingdom than in the Middle East and Europe, and is frequently described by supporters of the war as a "kangaroo court". Its members are not popularly elected.
A series of hearings is taking place under the title of the "World Tribunal on Iraq" with the purposes of:

- Hearing evidence in respect of any claim that the launch of the war in Iraq was a criminal act.
- Hearing evidence in respect of any alleged international criminal conduct during and as a part of the war in Iraq.
- Investigation of the doctrines espoused in the war (by all sides) and the economic connections which some allege are connected with the decision to wage the war in Iraq.
- To reach a decision based on evidence and expert testimony in respect of these issues and the war in Iraq."

"The Iraq War left many people dead or injured, and some sources have identified significant War crimes or Crimes against humanity in its conduct, as well as mainstream media coverage of breaches of the geneva Convention such as at Abu Ghraib, and the use of depleted uranium. According to UN estimates, a further million people died during the trade embargo (imposed by the UN following Iraq's 1990 invasion of Kuwait), due to malnutrition or lack of medical supplies, from sanctions targeting domestic water systems (History of Iraq). Many hundreds of thousands of these were children (whose deaths were documented by US military and are available on US military declassified websites). In addition, few commentators believe that under 100-200,000 civilians died as a result of other acts during the 2003 war.
Although other crimes are investigated, such tribunals require a lot of political will and strength to set up and few commentators appear to believe that a formal tribunal such as the Nuremberg Trials or the International Criminal Tribunal for the Former Yugoslavia will be established. In addition the US has refused to ratify the International Criminal Court established for the purpose of investigation international crime. In the light of perceived growing tendencies to ignore international law, this tribunal was formed to investigate the concerns of other groups and onlookers into Iraq. "
Source and further information:
http://en.wikipedia.org/wiki/World_Tribunal_on_Iraq

Further information:
Obama’s Plan Regarding Bush Era War Crimes
Michael Haas

Because the crimes were committed against brown-skinned people with lots of oil in their soil