There is a pretty good book from Allan Hirt on HA. http://www.amazon.com/Pro-Server-2005-High-Availability/dp/159059780X/ref=sr_1_1?ie=UTF8&s=books&qid=1268933692&sr=8-1
In terms of indexing, I might recommend Inside SQL Server book (http://www.amazon.com/Microsoft-SQL-Server-2008-Internals/dp/0735626243/ref=sr_1_2?ie=UTF8&s=books&qid=1268933727&sr=1-2) or Grant's (http://www.amazon.com/Server-Performance-Tuning-Distilled-Experts/dp/1430219025/ref=sr_1_1?ie=UTF8&s=books&qid=1268933755&sr=1-1)
