I read the SQL 7 and 2000 version several years ago (the 2000 version was very similar to 7)

http://www.microsoft.com/MSPress/books/4297.asp

and was interested to see that the new version will be broken down into three sections

http://www.microsoft.com/MSPress/books/8564.asp

http://www.microsoft.com/MSPress/books/9615.asp

http://www.microsoft.com/MSPress/books/7436.asp

The first two are written by Itzik Ben-Gan - more details can be found here

http://www.sql.co.il/books/insidetsql2005/

All books will be available in the first half of 2006