A lot of REALTORS and mortgage brokers seems to be on different pages when it comes to the various letters that the broker should supply to the borrower.  Below is a short list of these which any mortgage professional should willingly provide "free of charge."

PRE QUALIFICATION - This is a simple document that really has limited meaning.  It states that a borrower has been examined by the loan officer and found to have sufficient income, job history, and credit to take out a mortgage loan.  This letter usually does not (in my opinion should not) state a maximum amount for which the borrower qualifies.  That amount should be between the borrower and loan officer.  If the borrower wishes to share it with a REALTOR it is his/her prerogative.

PRE APPROVAL - This letter has a bit more meat than the previous one.  It is issued only after the loan officer has provided information to a lender and the lender has agreed that they will be able to provide a loan to the borrower upon verification of the information supplied, maintenance of credit and job status, and acceptable appraisal and title for the property chosen.

LOCK LETTER - This letter can be quite meaningful, or quite meaningless depending on when it is issued.  There are a couple of reasons for this.  First, it can be issued based on totally unverified data.  In fact a loan officer can obtain it based on estimates of income and credit.  Secondly, this letter will always have an expiration date.  Depending on the company one locks with the length of the lock can be from 7 days to 120 days.  The greater the length of the lock period the greater the likelihood of a higher interest rate. Underwriting may find issues that negate the lock, as well.

To be meaningful, these letters should have, at the least, been based on verified credit scores, income check (paystubs are a minimum), and debt ratio.  As well, it makes more sense to have this letter issued after an accepted Offer to Purchase has been executed. 

CONDITIONAL APPROVAL LETTER (or Conditional Commitment Letter) - This one is a bit tricky in some ways.  This is issued when underwriting has approved the loan, but their are still conditions to be met before documents are drawn and the loan is cleared to close.  The conditions are generally "gimme's" like a verbal verification of employment the day before closing, or a review of a minor appraisal issue.  Occasionally the condition is as simple as a change in the mortgagee clause on title or home owners insurance.

CLOSING LETTER or Commitment Letter - This is the guarantee that the loan is approved and will close unless the borrower changes his/her mind.  It should only br issued after the lender has provided the mortgage professional with a "clear to close" document.  If issued without lender "clear to close" it is pretty much worthless as the lender has not committed to fund the loan yet.

Will all of these be issued?  Probably not, and in fact, the borrower may not see some of them at all.  For example, the commitment letter is generally conveyed directly to the REALTORS. Or, a pre qualification may not have been sought before going house shopping and making an offer.  A lock letter may not be issued in the case of a borrower whose credit doesn't allow for conforming lending since subprime lenders often don't lock rates until closing.

REALTORS and borrowers both are well advised to talk to the loan officer to see what letters he or she issues and if there is willingness to issue other letters.  Also, it doesn't hurt to check and see what the loan officer thinks these letters represent.  Now id not the time to be working with people not knowledgeable in the field.  Nothing can replace experience in today's markets.