DJB (formerly a resident of Pewaukee) analyzes the claim by the Rajah Sulaiman Movement of responsibility. In addition, he provides analysis of the event and others affecting the Philippines. Be sure to read Manuel Quezon III's analysis of events too he looks at the leading theory the authorities had (or have) about the bombing actually being a freak LP tank explosion and does not dismiss it outright.
For up close and personal photographs of the bombing see Disney Cute Land's photographs. Disneycuteland claims to have been in the immediate vicinity of the explosion and publishes 43 photographs.