I am assuming you mean North Bridge / South Bridge...
Northbridge is the Memory Controller, that transfers data and instructions between the CPU, RAM and PCIe Devices.
SouthBridge is the storage controller, that controls how data is transferred onto storage devices (Hard Drives)
FSB is the physical bus that connects the North Bridge to the CPU and RAM. Current generation processors build the NB into the CPU, so all memory functions are controlled on chip removing the need for a FSP. Currently "Chipsets" connect the PCI devices to the CPU / Memory. (E.g. Intel X68 Chipset)
Sort of. In the traditional sense the NB handles RAM and GPU traffic. The SB handles SATA/IDE ports, audio, lan, etc. All the onboard devices usually go to the SB, then to the NB, then finally the CPU. If the GPU is on a PCIe bus, then the "PCIe" is handled by the NB.
Things changed a bit when AMD/IBM put the memory controller on the CPU. The CPU could directly get info from the RAM without needing the NB. At this point the NB started to only handle GPU duties. Intel then put that on the CPU as well, so the NB is pretty much gone. The rest of the PCIe slots usually talk to the SB. (there are some odd boards that have PCIe 16x slots that go to the SB, or to another chip. (NF200) These aren't very common but they do exist.)
Why are you asking if you can look up the info on wiki? And seeing as your there, what is the Back Side Bus?
Check out some old Socket 775 reviews and look at the block diagrams they have. If you follow the lines you should see how everything is connected to each other. For today's CPUs the NB is inside the CPU core, so just imagine the NB gone and the CPU itself handling its duties. The FSB is also gone. There is still a link between the "SB" and the CPU, but its a high speed serial bus now instead of a slower parallel bus.