Here is a list of all ongoing rebates and instant savings offered by the major camera and lens manufacturers:
Nikon
The current Nikon rebates are set to expire on June 29, 2013:
Fujifilm
Fujifilm's combo savings will end on June 29th, 2013:
Canon
Canon's rebates will be expiring on June 22nd, 2013:
Sony
The Sony cameras and lens bundle deals will end on June 29, 2013:
Olympus
The current Olympus savings are valid till June 22. 2013:
Tamron
The savings on Tamron lenses will end on June 30th, 2013:
Sigma
The current Sigma savings will expire on June 30th, 2013:
Tokina
Tokina's mail-in rebates end on August 31, 2103: