As Google Sky View and the Sky Forum develop, some thoughtful members are sharing some useful tools.
The following links will take you to the original posts where these members have shared their goodies with us.

Sky Data Problems Compendium

wcs2kml

Horizon Add-on

Sky KML Guide

Where is Hubble now

Angular Scale in Sky

Angular Scale in Sky ( updated version KML)

Best of Hubble, maybe not a Tool but very Cool

syzygys APOOD Post

Spreadsheets Sky Calculator

Real Sized Planets in Google Sky

Satellites in Orbit

ADD2SKY V1.0 (POST)

Orbiting Frog

Many thanks to these members for their contributions.