Looks like there is a newer version of SmartPhoneTracker if you search google. I've tried it and I am not sure how reliable it is... I have really weak service out here at work so it could be messing up because of that.
I am going to try another one that I found in one of the threads:
http://remotetracker.sourceforge.net/index.html
It doesn't look like it is quite as simple to use, but it also has a lot more commands that you can send it and maybe it will stay hidden better. Utlimately I'd like to see these cooked into the roms with some default configurations... or if there was a way to upload a config file and store it into the ROM so that if someone did a hard reset on the phone the config would still be loaded and the program would be set to run as a service by default.