Yes, absolutely we had this done as soon as the vet said it was time... I think she was 5 or 6 months old at the time. She is strictly an indoor cat... always 100% of the time, so it wasn't to prevent babies. I've heard that there are definite health benefits to getting cats spayed, especially when they get older. Plus of course it prevents the discomfort they'd have to go through while being in heat.
There's a bad memory associated with that time period, though... when we brought her home from the overnight hospital stay, she tried to jump up on the bathtub before being fully healed. I'll never forget that scream when it hurt her so badly.