This web site will allow you to quickly generate simple horoscopes and file them away. Keep in mind that this is a very simplified horoscope system, and is intended only to demonstrate some AJAX programming principles and to show off some astrology code that I had lying around from years ago. If you want a really thorough, professional system with high accuracy, detailed options, and innumerable professional upgrades, try AstroDienst. Alternately, if you want a custom astrology system built for a fee, I can certainly do that through Lunar Logic. :-)
Accounts - Registering and logging in is as simple as possible: just provide an email address and a password. The registration form and login form are one and the same. The email address will be used only to do password reminders. You won't be able to save charts until you register.
Time zones - To calculate timezones, rather than taking the time to integrate a commercial package, I wrote my own time change library in JavaScript. It occurred to me that timezones, even though they are traditionally considered the most annoying part of the calculation of a horoscope, can be calculated with certainty fairly often. I thought I would start with the clearest, simplest and best observed rules and work my way downward until I reached a point of diminishing returns. After all, the daylight savings time rules have been rather clear since 1966, and determining the time zone is easy for 3/4 of the states. The amount of code to be able to be right on 50% of the time and really close 25% is not that much.
Latitudes and longitudes - I downloaded 25,000 or so records from the US Census bureau, so the database only covers the United States at this point.
User Interface - My main emphasis was on the data entry area. I wanted it to be as easy as possible to enter birth information.
Interpretations - Sorry, none yet.
-- Mark