Here is a fairly good analysis of the age of the earth from a Christian scientist who does NOT believe in evolution (therefore, no one can argue that he is influenced by the need to have an old earth to accommodate evolutionary time frames):
http://www.reasons.org/resources/apologetics/moreland_jp_age_of_earth.shtml?main
http://www.reasons.org/resources/apologetics/moreland_jp_age_of_earth.shtml?main