How to play PC games using your Mame controller

[nycjsw]

This is probably a really dumb question.  But I want to use my Mame arcade machine to run PC games like Call of Duty or Far Cry.  The problem is how do I get my arcade controller to mimic the mouse with a fire button?  I had the same problem trying to play the game Frontline.  With a PC mouse you can look all around and shoot with one hand.  I can't to that with my trackball.   I guess I could but it would be harder since my hand would have to leave the trackball to fire.  My current setup has joysticks and 8 buttons for 2 players, a 4 way joystick, a spinner and a trackball.  Any thoughts or how do most people get around this problem.  Thanks