Editor's note: This is the first in a two-part series. The two most important pieces of information mortgage applicants should have in entering the market is their credit score and the appraised value of the property they are interested in buying. The first is easy; they can get free estimates on the Web, or buy their score for $25 or so. When they apply to a lender, one of the first things the loan officer will do is pull their credit online, which takes only a few minutes. Appraised value is another matter entirely. It has to be ordered by the lender after the borrower has applied for the loan. In most cases, the order goes to an appraisal management company (AMC), which selects the individual appraiser who does the work and delivers the appraisal report to the AMC, who deliver...