Here is my latest information, direct from Golden Caribbean, who are the primary organisation behind the Monarch service to Tobago.
Monarch will stop flying to Grenada on 25 April 2012. The flight will continue flying to Tobago as a direct non-stop service until 12 September 2012. The Monarch service will then cease until either 5th or 12th December 2012 when it will resume the non-stop direct service until the end of April 2013. It is hoped that this will continue in the summer of 2013, but plans have not been finalised at this time.
So, very good news for Tobago lover in the short-term.
As a matter of interest to the general public, the Monarch flights to Tobago and Grenada are sponsored by their respective local governments/tourism departments. Grenada is no longer willing or able to subsidise the flight, hence the reason the service is to be discontinued. Hopefully the local government in Tobago will appreciate the vital importance of continuing this flight and continue to sponsor it. Fingers crossed!
myTobago.info - the definitive Visitor Guide to Tobago