Yeah, the sepcifications for some of the AMDs get a bit fuzzy at times. Intergrated into chip simply means that they've built the memory controller into the chip therefore the FSB is eliminated and we have a new high bandwidth, low latency bus, called hypertransport. All socket 939 chips will have the 1GHz Hypertransport speed, which is what the "FSB" speed of the Sandy up there is refering too. Basically, both the Clawhammer and San Diego have intergrated FSB and 1GHz hypertransport buses.
The FSB speed isn't locked on any chip, ever, so don't worry about that ever.
As mentioned above, the San Diego are the superior cores to the Clawhammers for the above listed reasons.