(In Windows)
Get a Windowable chess game, such as Winboard.
Size it as big as you want on the screen
Make sure the whole of the chessboard is visible
Make sure the colors of the board and pieces are what you want
Alt-PrtScr to copy the top window.
Paste it into your paint program (mspaint, irfanview, etc)
Crop the board
You can even use RHP as your source. Create a set position game and no pieces on the board. Print from browser OR Snapshot the browser window (alt-prt scr), paste a blank board to your paint program, crop, print. Then, populate the set piece board with two sets of pieces (if you want the pieces to be on the other square color, and you're going to cut square shapes instead of piece shapes.) Otherwise, snapshot the Piece Shape chooser window, paste or print directly from browser and cut the individual pieces.
Really, this is harder to explain than it is to do.