Source: Half-Life Fallout

Erik Johnson from Valve reported in the comments of CS Nation that they are working on more content for Counter-Strike: Source. Old maps, new models and even a brand new map for the game:

We're working on porting some more of the classic maps right now, currently de_prodigy is in the works. We'll be releasing this as quickly as they are completed.

We're also working on one original map, which will begin internal playtesting this week. This still means we have a fair amount of work to do on it.

We're also working on two updated player models.

Most of this is scheduled to be released in the December timeframe.

Erik