Heuristic Tic-Tac-Toe(VB)

CAn anyone tell me how to search a 3X3,4X4,5X5 and a 6X6 Tic tac toe state space using best-first or breadth first or depth first search or even minimax, and the computer is playing against itself and should keep track of visited paths.(Visual Basic)

Explanations and code for VB here http://visualbasic.about.com/library/weekly/aa093002a.htm