There are several sites on the web that offer information about the 4A. Even Texas Instruments has a page devoted to its orphan!
A good place to start is the “TI-99/4A Home Computer Page.” This page, maintained by Richard Polivka, contains a wealth of information, video clips of TI software in action, and many links to other sites. You can find it at http://w3.gwis.com/~polivka/994apg.html. I asked him why he started this page.
“When I started the page, it was just for nostalgia. I had started searching the web for ‘TI-99/4A’ and didn’t find much. As a matter of fact, I think all I could find was ‘The TI and Parallelcomputing Page’…You might want to contact him – I’m pretty sure that he was the first 4A page…I didn’t know that the newsgroup existed and was thrilled to find that there were still 99/4A enthusiasts out there. I started the page because I missed the good old days of programming on my 4A, and also because I wanted to try to archive as much 4A information as possible for all of the current and former 4A users. Things have slowed down a bit now, but the majority of the e-mail that I got wasn’t from those who still used their TI. It was from people who told me that they had used their 4A when they were in their teens, and credited it to getting them into their current field of electronics or computers.”
“I…usually get anywhere from 1000 to 2000 hits per month but past that I don’t keep too much track….I’m always one of the top 10 most requested directories out of those hosted by my ISP.”
This site includes several links to other sites. Some of the other sites listed below came from the list on Richard’s TI page.