Will the frequency 122.000 MHz no longer be used for Flight Watch after October 1st 2015?
Below 18,000 feet MSL, En Route Flight Advisory Service (EFAS) (a.k.a. Flight Watch) is provided on 122.0 MHz. Above this altitude, it is provided on discrete frequencies, with each one serving a specific ARTCC area (see AIM 7-1-5, FAA JO 7210.3Y Section 3).  These discrete frequencies are listed in the margin of IFR Enroute High Altitude charts:



To answer your original question, the FAA plans to consolidate EFAS onto existing Flight Service Station (FSS) frequencies on October 1, 2015. Because Lockheed Martin (the FSS contractor) has consolidated flight service stations, the EFAS weather briefers are now co-located with Flight Service personnel (they physically sit next to each other in the same room), making it possible to obtain both services on the same frequency.

At the same time, the FAA will phase out legacy Remote Airport Advisory Services and more significantly, require the ICAO format for all flight plans (international AND DOMESTIC), see Flight Service Program change announcement.