Custom field changes in Project 2010

Question

Is there a last-modified-date indicator in one of the databases to indicate when a custom field was changed? For example, I want to know when a custom field called project-phase (not workflow) has changed from one value to the next within a PDP. 
The purpose is to produce a report that indicates the progression of a project from one phase to the next (plan-analyze-design, etc.).

Answer 1

this question is closed - but for what you asked for the basic query provided  gave you the custom field modified date which would be more precise then the project modified date - 
The below query will get you the information you want
YOU put in the project GUID  OR the GUID of the Custom Field and this will return the tasks and project name it will also show you the difference (at least it did in my DB) the project modified data versus the task/custom field modified date which is
also what you asked for...
USE ProjectSevrerDraft
SELECT
mscf.MD_PROP_NAME as "Custom Field",
mstcv.MD_PROP_ID as "MD PROP ID - can remove",
proj.PROJ_NAME as "Project Name",
proj.MOD_DATE as "Project Modified Date",
mst.TASK_NAME as "Task Name",
mstcv.CREATED_DATE as "Task Created Date",
mstcv.MOD_DATE as "Task Modified Date"
FROM MSP_TASK_CUSTOM_FIELD)VALUES mstcv
JOIN MSP_PROJECTS proj
ON mstcv.PROJ_UID=proj.PROJ_UID
JOIN MSP_TASKS mst
ON mstcb.TASK_UID=mst.TASK_UID
JOIN [ProjectServerPublished].[dbo].[MSP_CUSTOM_FIELDS] mscf
ON mscf.MD_PROP_ID=mstcv.MD_PROP_ID
-- You can select either below un-comment out the '--'
-- And insert what you want - the project or Custom field
-- GUID will help. The PROJ_UID is found under MSP_PROJECTS
-- THE MD_PROP_ID is found under the published database in
-- the MSP_CUSTOM_FIELDS table
--WHERE mstcv.PROJ_UID =' GUID OF PROJECT'
--WHERE mstcv.MD_PROP_ID = 'GUID OF CUSTOM FIELD'