OpenSUSE Network :: Connected To Internet And Also Connected Pcs Might Want To Use Internet?

I want to set a up a network of inter connected pcs, for example on pc A linux is installed.now pcs B, C , D, etc should connect to A and do there work, for example A want to do C/C++, development, whereas B wants to do some PERL development or whatever, this is just an example, 2 different pc users might do same work also, and the connecting pcs may have Windows or linux or bsd.OSes now what h/w or s/w is required and what steps are required to set up this network, main pc would be connected to internet and also connected pcs might want to use internet also..have installed opensuse edulife , and use this as PC A for testing.. and I use bridged dsl Broadband connection to connect to internet , by the username and password provided by the ISP, in windows its easy to setup this connection, however not able to do on linux,