There are many books available in the market for BizTalk Server like Pro BizTalk 2010 which is one of the best book to learn the BizTalk server.
Also there are websites like BizTalk Guru's which is having lot of application and other guidance material.
Hope it will be helpful to you.
Pawan Awasthi(DNS MVM)
+91 8123489140 (whatsApp), +60 14365 1476(Malaysia)