in wisconsin, they are actually thinking about opening a hunting season on stray/feral cats, with no bag limit. no joke.
i have always used haveaheart live traps and had great luck. i do not care if it is a neighborhood cat. leash law is leash law. when you catch cats with parts missing, bones showing, visable maggots in sores... you are doing the right thing, although, if you want to get rid of them, without the fear of breaking the law, just set up a line of live traps (if your problem is bad enough) with some wet, cheap cat food in them, and when they are full, call animal control. they know my house, and where to get the traps when i say they are full. they just re-bait them, and set them up again for me if i am not at home. saves them work. nothing catches a cat better than wet cat food, and two other traps with cats in them - the next traps will be filled soon - he'll be called in - naturally. effortless, fun hunting.