Tom, had the same problem with a fly inside my 65 inch. Other than an annoyance, there is no harm but my service plan covered having a guy come out to remove the bug.
I have this problem at the moment with my Philips 55" Widescreen. Previously the spider at least moved around for awhile until it finally went away, but at the moment there's a web streaking across the screen! I'm out of warranty already, anyone know if it's relatively easy to open the cabinet up to clean the inside of the screen?