ISE Webpack is a free subset of ISE Foundation series. It has support from Web only and lacks some parts like CoreGen, MXE, ISE simulator, ChipScope etc and is for Educational purpose only. But it supports all the new Xilinx FPGAs.
No it isn't like there is no need to connect to xilinx server to synthesize your code in ISE web pack, basically ISE webpack can be downloaded from xilinx site and one can synthesiz a limited number for CPLD/FPGAs devices from xilinx while in case of ISE foundation one has to buy the tool and it works for all CPLD/FPGAs of xilinx. there are various features which are not available in ISE webpack, but still for a beginner it is good to start with ISE webpack.