The most common way to measure the height of mountains is the height above sea level. In this case the highest peak is indeed Mount Everest in the Himalayas.
The Earth is not completely round; its spin causes it to flatten at the poles and bulge around the equator. If you measure the height from the center of the Earth the highest peak is Chimbarazo in the Ecuadoran Andes.
If you measure height above ground Hawaii's Manua Kea would be highest since it towers higher above the ocean floor than the height of any mountain on land.
the highest peak in the world is Mount Everest which is 8,848 metres (29,029 ft) above sea level and its in the Himalayas in Asia.
its that mountain in nepal isnt it... everest :S