Here are some maturity models I've found useful.  For commentary, the CBDI material is insightful.  The Oracle model is very useful - especially the summary commentary on pages 7 -8.

The Sonic Software model is being proposed as an industry standard, but it lacks the dimensions of the Oracle model.

CBDI Maturity Model - CBDI journal2005-12.pdf

oracle-soa-maturity-model-cheat-sheet.pdf

soamm_quick_reference.pdf

Sonic SOA Maturity Model.pdf

Rashid Desai Shaping The Organization In Institutionalizing SOA 10312006.ppt

Sun soa_readiness.pdf