The only preachers who claim Christ descended into hell after His death on the cross are those who have departed from the Truth. If "most preachers are saying" what Joel Osteen says, you are listening to a group of deceivers. That it's a popular lie doesn't make it true.
You can read more about Osteen and his ilk at these links:
http://christianunplugged.com/judgingabook.htm
http://www.ccwonline.org/osteen1.html
http://www.apprising.org/archives/2005/10/the_truth_turne.html
And you can read my view on similar topics here
http://brogdensmuse.menofhonorministry.org/Apologetics.htm
The bottom line - let the Word of God (not the words of man) richly dwell in your mind.
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Now that he ascended, what is it but that he also descended first into the lower parts of the earth (Eph.4:9)
By which also he went and preached unto the spirits in prison (1Pe.3:19)
Christ went into the part of hell known as 'Abraham's Bosom' to release those OT saints who went there while waiting for Christ to pay for their sins (Lk.16)