After posting about the "Typealyzer," I found a site that is much better. Really outstanding. It's called Signal Patterns and is now in beta. Since I am a psychologist by training, I know a lot about personality tests. There are a very few good ones. On the 'net, there are even fewer. However, this site has tests that are based on solid, valid and reliable research. I definitely endorse it. BTW, the charts are very, very cool!
(Note: that was 2008 - it is now 2014. Since I wrote the above post, this company has made some changes. I'm hearing a bit of worrisome feedback from readers, so will go back, take a look, then - if warranted - revise this post... all the while reminding myself that it's progress, not perfection, that counts.)