Hello,
I'll try to clear up your confusion..
Apache is the short name of Software Foundation
(http://www.apache.org/), a group under which umbrella different
software ist developed - for example the Apache HTTP Server
(http://httpd.apache.org/ - also known als Apache HTTPD - for HTTP
daemon)
On most Unix distributions the Apache HTTPD executable is called
httpd. I _guess_ this has more or less "historical" reasons, or
compatibility reasons. It's just the executable though - not
necessarily all files used to run it properly.
apache_1.3.27.tar.gz is version 1.3.27 of the Apache HTTPD, while
httpd-2.0.43.tar.gz is obviously version 2.0.43 of the Apache HTTPD.
The 2.x version has been heavily rewritten and The Apache Group chose
to call the files httpd-2.x.tar.gz instead of apache_1.3.x.tar.gz -
please don't ask me for the reason, I don't know

But both of them
are probably the Apache HTTPD, so you do not need both but only when.
(Which one to choose? - search on Google groups for one of the many
threads about 1.3 vs 2.0)
You can also look up some non-existing page on your server (like
http://127.0.0.1/blablabla) which probably will send you the version
information in the page footer.
I hope I could help
Regards,
johannes
>> Stay informed about: apache vs httpd??