I can wholeheartedly suggest the following titles -
Oracle Service Bus 11g Development Cookbook
by Guido Schmutz et al.
Oracle BPM Suite 11g Handbook (Oracle Press)
by Manoj Das et al.
Oracle SOA Suite 11g Developer's Cookbook
by Antony Reynolds & Matt Wright
The following from Bruce Silver is a great book on BPM per se.
The following title from Lonnike Dikmans et al. is a great intro to SOA per se.
Still a very useful read from Jeff Davies et al -