As you may or may not know, the BCS and the ISTQB formed an agreement in 2010 that effectively merges the ISEB and ISTQB software testing certification paths. In the past, the BCS managed ISEB certifications (primarily a UK certification) and the ISTQB managed ISTQB certifications (the global equivalent of ISEB certifications). However, this was inefficient because both certification paths are extremely similar. Thus, the decision was made to basically combine the two.
Previously, the ISEB certification path encompassed ISEB Foundation, ISEB Intermediate, and ISEB Practitioner (2 modules). The prior ISTQB certification path encompassed ISTQB Foundation (CTFL), and ISTQB Advanced (3 modules).
Now the new combined certification path will be as follows: ISTQB Foundation, ISEB Intermediate (optional), ISTQB Advanced (3 modules), and ISTQB Expert (multiple modules, not yet finalized). As you can see, with this merger the 2 ISEB Practitioner certifications have been withdrawn (effective April 2011).
As can be expected, this leaves the people who have earned one or both ISEB Practitioner certifications a little in the dark. The good news is that even though the Practitioner exams are no longer offered, they will continue to be recognized and valued within the software testing community.
Additionally, holding one or both of these certifications can essentially be used as credit for one or more ISTQB Advanced certifications. Now by credit, I do not mean substitution; I mean that these certifications can be used to meet certain ISTQB Expert exam prerequisites.
Specifically, if you earned your ISEB Practitioner certification prior to April 2008 (when a single syllabus and exam covered both modules), then you can take any ISTQB Expert level exam for which all 3 Advanced-level modules are prerequisites. If you earned your ISEB Practitioner in Test Management certification after April 2008 (when the exam and syllabus were split into two modules), you will be able to take any ISTQB Expert level exam for which having an ISTQB Advanced-Test Manager certification is a prerequisite. If you earned your ISEB Practitioner in Test Analysis certification after April 2008, you will be able to take any ISTQB Expert level exam for which having an ISTQB Advanced-Test Analyst certification is a prerequisite.
The bottom line is that if you have one or both ISEB Practitioner certifications, do not fret. These will still hold value, and can be used as stepping stones for certain ISTQB Expert level examinations.