Sorry, I can't point you to any particular site. You haven't given us much
info to go on...
However, I can make a coule of suggestions...
In my (fairly limited experience) cash drawers are usually driven by a
special interface on a receipt printer.
If this is the case with the cash drawer you have, I would suggest you start
looking on the website of the receipt printer manufacturers, there maybe
some drivers you can download to program against...?
Otherwise, I assume the cash crawer has a serial/usb connection, in which
case, you need to know which serial/usb codes/signals it responds to. I
suggest you do a Google search for help on programming the serial port.
Good Luck!
ChrisM