Set your DVD player to 1080i or 720p so there is no conversion.
There will still be conversion. This is a fixed pixel 768p display. 1080i will go down to 768p, and 720p will have to go up to 768p.
#1) You can use other people's calibrations as a starting point, but they won't be optical for your environment. You will have different windows, different wall or floor coverings, different paintings and other things that will reflect and refract light differently than the viewing environments of others.
To deal with overscan...
http://consumerist.com/368198/circuit-city-will-access-a-secret-panel-in-your-tv-for-10474#c4735236
#2) Digital Video Essentials Blu-Ray (or HD DVD if you just happened to have/buy one)-- it is not easy to understand/use... You should also get an Eye-One LT colorimeter for greyscale calibration. You can also download the AVS calibration disc and burn it to a compatible disc.
http://www.avsforum.com/avs-vb/showthread.php?t=948496
Ultimate DVD is good for beginners. You can use that on your upscaling DVD player as a starting point. Avia is also good, but be warned that it has accuracy issues with its greyscale.
#3) Yep... That sounds about right for a 768p display. Honestly, on anything under 65", 1080p is overrated for average viewing distances. Your display will convert 480i/p, 720p and 1080i (maybe 1080p) to 768p. When your Sony handshakes with your display via HDMI, it asks the display what resolutions it supports. Your display supports up to 1080i in. This is fine. Honestly, you may want to do 720p in as you're converting from 480i to 1080i then back down to 768p. You probably just want to go 480i->720p->768p unless your upscaling DVD doesn't de-interlace properly.