I'm a huge fan of poisoning the buggers out of existence, grew up on a farm and it's amazing how much damage they can do to grain. Some people worry about their other pets and it is a viable concern. My family has never poisoned a family pet but I know people where that has happened.
You can go the trap route if poison is a no go. Traps do a pretty decent job of getting rid of rodents so long as you don't mind disposing of them after being caught.