Oh, thanks for those! The TolWeb site looks just right for me at the moment (although I think I'll eventually spend lots of time at both): Lots of footnotes and links to other sites, which I always appreciate. This stuff has always been confusing to me. Thanks again. Cheers!
You're welcome. I actually love to just play around with the NCBI taxonomy website. The history of life really is not what you would expect simply by looking at things.
Since it seems like you like this kind of stuff, I'll give you another thing that I like to play around with (but you will have to do a little research on your own to know how to use it). The clustalW site (http://www.ebi.ac.uk/clustalw/) can give you the approximate taxonomic relationship between whatever sequences you enter into it. For example, I think the last time I did it, I used Rag (recombination activating gene), because it was a gene that I was working on.
I looked up the Rag gene sequence (on NCBI) from a few mammals, and plugged it into ClustalW. The comparisons of this one relatively short sequence (a few thousand nucleotides) almost entirely matched up with the taxonomy that thousands of people have worked on their entire lives. And that will be true for whatever gene you pick to plug into ClustalW. This is not something that only biologists can do. You can prove to yourself, without giving the ClustalW program any indication of which organism is which, how the tree of life has worked itself out.