The folks over a Jalopnik have spotted a 2008 CTS parked on the side of a Detroit area street.
Expect the new CTS to go on sale to the general public starting late this summer/early this fall. Additional variants (the as yet unannounced coupe and the CTS-V, for example) should show up in a year or so.
They have posted an entire image gallery of the car they saw over at:
Jalopnik: CTSpotting – 2008 Cadillac CTS Spotted In Royal Oak, MI