The Oracle Middleware Fusion 11g stack has a certification path for SOA:
1Z0-451 Oracle SOA Foundation Practitioner.
When you pass this exam you may call yourself: Oracle Service Oriented Architecture Infrastructure Implementation Certified Expert.
Today I passed the exam with 81% but I must say the questions were pretty detailed.
So you really must have practical experience with the Oracle SOA Suite 11g, but this is a good thing because that is where Certification is for.
* Follow a SOA Suite 11g Bootcamp (or follow the book: Getting Started with Oracle SOA Suite 11gR1)
* Play with the product at home
* Follow the recommended learning path as mentioned here (for this you must be a registered Partner)
The questions are of high level and detailed level, with Choose Applicable, True/False, and Select Correct type of questions.
A CIBER colleague of mine also passed this exam: Michel Christianen.