My husband applied in January 008, and the interview was in May, 2009.
However, things seem to be going faster at that embassy lately. One forum member who sent in a very detailed, well-organzed application (800 pages or so) had it processed in just 2 o 3 months. A couple of others also got their visas quickly.
Keep in mind that Accra is a difficult embassy that rejects half of all spousal PR visas, so you have to send in a lot of evidence that your relationship is genuine, much more than you would need to send if you were applying from a Western country.