Sample Letters
General Notes:
If you know the name of the person who will be getting the query, use the name.  Otherwise, address the correspondence To Whom It May Concern.  Initial contact should address the reviewer as Mr., Ms. or Mrs. as appropriate.  Follow the reviewer's lead with future correspondence.  If the reviewer starts using your first name, address him by the first name in future correspondence. 

These samples are merely guidelines, and should be tweeked as needed depending on the market and information available from the review's website.
Query Letter:

My name is Jane Doe.  I would like to submit my book, The Book of Doe, for your review.  The Book of Doe is a coming of age tale set in the 1970s.  The protagonist is a spoiled rich girl who suddenly finds herself forced to fend for herself after her parents die in an accident and her uncle, who is the executor of the estate, cheats her out of her inheritance. 

The Book of Doe
Jane Doe, author
ISBN 1234567891111
Softcover, 243 pgs
General Fiction
Availability:  The book is available on Amazon and from most booksellers.  Distributed by Ingrams and Baker & Taylor.

More information about the book can be found at http://www.mywebsiteurl.com.  If you have any questions, please let me know.  I would be happy to send you a complimentary copy should you wish to review the book.
Reviewer Declines:

Thank you for your prompt reply to my query.  I appreciate your time, and hope we can work together in the future.
Reviewer Accepts:

Thank you for your prompt reply to my query.  I appreciate the opportunity to send you a copy of my book for review.  As soon as the book ships, I will provide you with the shipping details. 
Shipping the Book:

Just wanted to let you know that I have shipped your complimentary copy of The Book of Doe for review.  The book was shipped via USPS Priority mail.  The tracking number is 123456789.  It should arrive within two to three days.  I will follow up with you next week to make sure the book arrived.  If you have questions before then, please let me know.
Following Up:

I am following up with you to ensure that you got the comp copy of The Book of Doe that was sent last week.  If you have not gotten the book, please let me know so that I can follow up with the Post Office. 

Thank you again for taking the time to review my book.  I look forward to your comments. 
After Getting a Positive Review:

Thank you so much for your wonderful review.  I am glad that you enjoyed the book.  I appreciate the time and effort you put into reviewing my work. 

I will be sure to keep you and your site in mind for my next publication.  If I can ever be of help to you, please do let me know.
After Getting a Negative Review:

Thank you for taking the time to review my book.  While I am dissappointed that the book did not meet your expectations, I found your comments insightful.  I will keep them in mind for future projects. 
After Getting an Abusive Review (should be addressed to the site admin, not the reviewer.  If the reviewer and the site owner are the same, then obviously you don't get a choice.)

I would like to thank you for giving me the opportunity to have my book reviewed by your site.  However, there are certain aspects of the review that concern me personally.  While I respect the fact that the reviewer did not enjoy the book, some of the comments seem personally targeted at me. In particular (specify the offending comments).

Such comments do not live up to the standards set by your other reviews.  I would appreciate it if the offensive comments were deleted from the review.  If this is not possible, then the entire review should be removed.  I appreciate your understanding in this matter.