First off, could you give more detail as to what you need? As I understand it, Kirchhoff's First Law is an equation regarding electrical flow across circuit intersections; Wikipedia gives the informal form of it as:
At any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node, or: The algebraic sum of currents in a network of conductors meeting at a point is zero.
When you say you need the program to 'illustrate' Kirchhoff's First Law, do you mean it should calculate the values coming into and out of the node, from and to the given circuits; or that you need to simulate the circuits visually, as a circuit diagram (which would require the former computations, as well as the graphics handling)? Do you need to simulate a specific circuit that can be hard-coded into the program, or (more likely) does it need to be able to take a set of circuit definitions and translate those into the combined circuit?
Also, could you show us what work you've already done on the project? One of the rules of DaniWeb is that you need to show your effort on the project, in part so that we know where you are in it and don't duplicate work you've alrady done, and partly so we can tell that you have put a good-faith effort into the project yourself before asking for help. What code have you written for this so far, if any?