This is my script
>>> import arcpy
... import os
...
... mxd = arcpy.mapping.MapDocument(r"G:\GIS\Maps\Projects.mxd")
... df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]
... df.time.currentTime = df.time.startTime
...
... while df.time.currentTime <= df.time.endTime:
... # An example str(newTime) would be: "2008-12-29 02:19:59"
... # The following line splits the string at the space and takes the first
... # item in the resulting string.
... fileName = str(df.time.currentTime).split(" ")[0] + ".pdf"
... arcpy.mapping.ExportToPDF(mxd, os.path.join(r"G:\GIS\GIS_Analysis\CS_Working_Group\Time Maps", fileName), df)
... df.time.currentTime = df.time.currentTime + df.time.timeStepInterval
... del mxd