It might depend on the severity, but in most cases working out should be fine. I worked out with an uncorrected inguinal hernia (fairly small) for a couple of years, without a problem. It affected my exercise selection a little: I could do leg presses as heavy as I wanted (north of 1000), but if I did free weight squats above 155, my hernia would pop out -- which I wanted to minimize to prevent/reduce growth of the hernia until I was ready for surgery. Unless you have some reason to know you are an acute risk for strangulated hernia, I'd say go for it, and just pay attention to how various movements affect you.
