I found a VERY cheap solution with a $40 GPS-enabled cellphone and a pay-as-you go from BoostMobile. There's an app called "MapQuest FindMe" that is only like $5, and it works like a charm. I just put all of the phone's sounds on "silent," put a small piece of black electrical tape over the speaker just in case I had missed any, and put it in my son's baseball gear bag in the trunk of my wife's car. You can then just log onto a secure website any time you want to, and see where the phone is located down to about 50'. You can even set it to e-mail you alerts when it comes within a user-defined distance of any user-defined location -- say, 100 yards of OM's house, or of your wife's place of employment.
Other than having to retrieve it every night to recharge its battery, it worked like a charm, giving me accurate readings (of which I captured some pretty damning screenshots) about 98% of the time.
