I lost my HTC EVO 4G phone this week. I don't know for certain whether GPS is enabled and I've never installed any android apps to find a missing phone. Is there anything I can do from my Sprint on-line account to locate my phone? Can I turn on GPS remotely?
You can try using an application called Plan B for Android. It remotely installs to the device as long as it is powered on and sends you maps of locations to your email account. If GPS is not turned on, it will not be as accurate, but still better than nothing.
I have Seekdroid (Paid) and can do several functions to the phone remotely including lock it, wipe it, remotely enable GPS and locate it, sound an alarm with a custom message, as well as retrieve the last few phone numbers called in case someone is using your phone. There is a free version as well that has most of the same features. I know the app install can be pushed to the phone like anything else installed from the market, but I believe the app has to be launched at least once on the phone for it to work. Look into it if you do retrieve your phone.
I would say go through the market apps and see if any do not require a setup launch on the phone to be activated. The Google Latitude idea is a good one as well if you enabled it. I believe HTC Sense has a built in security software if you enabled "Find Device" in the location settings. Problem is the beta site is truly beta and everything doesn't always work.
Sprint Family Locator is always an option as well, I'm not sure if there is a free trial still running on the program or not, but the $5 would be worth it if the phone ends up being found.