Clarify Tax Credit Please

Can anyone out there answer a question I have on the tax credit? My husband and I are looking into adoption and attended a meeting in the fall of 2004. We thought we understood but now we're a bit confused. If we proceed we will be dealing with an independent adoption service. We will put out approx. $4,000 in 2005 (we are taking the summer off and would contact the center in October) for the home study and to be put in "the book". This process would take about 4-6 months which would put us into 2006. We're told we don't need to put out any more $ until adoption is finalized. So on our 2005 tax returns we will only be putting out $4000 so can we only use $4000 of the $10,000 tax credit or do we use all $10,000? Where we are confused is because we were led to believe that we would use the tax credit in the year that we pay ANY expenses. We just don't know if it's the full amount or not. Can anyone help? tlbarry...