One user reported that the app doesn't work properly on the LG Optimus but didn't provide details. If you own the phone already, just get the app and let us know. If it doesn't work, you can always return it for a refund within 30 days - a short email is enough.
I just picked up the LG pheonix and the app seems to work okay on it with the exception of the satellite's being off. I watched the video for calibrating the compass but I can't figure out how to leave the app running while doing a compass calibration. I did not upgrade the android 2.2 operating system either.
You just wave the phone in this figure 8 while the DP app is running. At least on all the phones I know of. Also make sure that you don't use the phone in a case (or verify that the case does not interfere with the compass), stay away from anything metal and electrical.