After Firefox3.5 ("Shiretoko") is released, the next version of Firefox will be developed under the project name "Namoroka". The version number will be initially set to "3.6", but this should not be considered final, and as such the project may also be referred to as "Firefox.next". Namoroka will be based on Gecko 1.9.2, with an intended release target of early-to-mid 2010.

More info: Firefox/Namoroka

Source:→ Softpedia