I've never Overclocked before and I installed the milestone app, the phone seems to work fine at 1300 MHz and 80 LV
I'm assuming that that is 1.3 GHz, I had it up to 1.4GHz to run a quadrant test which worked and then I bumped it up to 1.45 and it black screened and I had to battery pull.
Right now I'm running a 1.25 GHz with a 70 LV, but how can I know that it's not harmful to my phone?
Like everything is running fine but is there any free app to measure the internal temperature of the phone and what are the acceptable temps?
And how long should I run the overclock without any problems before I apply it from boot?
Usually excessive heat and lockups are a sign that your OC isn't faring well. My phone is so picky I can't push it beyond stock speeds without it freezing and rebooting. I can usually tell after a couple of games of jewels or something similar if the OC settings are going to fly or not. Just my experience but I'm sure others have some better advice and/or tools.