I am assuming that you need to latch the output of some port such that the output of the latch remains stable while the port changes. This can be accomplished most readily with a chip, available from Radio Shack, called the 74HC574. Ground the output enable and drive the 8 data inputs with the 8-bit port. There is a clock input that "takes a snapshot" of the data on the inputs on the rising edge. Toggle this line with a single bit from another port. This URL will lead you to a PDF file detailing all the chips data http://www-us.semiconductors.philips.com/handbook/chapter_1906.html