Version: SCCM 2012 SP1 CU2
This will generate a list of all collections with maintenance windows. The description field contains the maintenance schedule. The duration is measured in minutes.
select SW.CollectionID, Coll.Name as 'Collection Name', SW.Description, SW.Duration as 'Duration Mins', Coll.MemberCount from v_ServiceWindow SW join v_Collection Coll on SW.CollectionID=Coll.CollectionID