phpmyadmin seems well documented to me, try:
http://www.phpmyadmin.net/documentation/
http://www.phpmyadmin.net/
I am using apache 2.0.36 / php 4.2.1 / mysql 3.23.52 - phpmyadmin works fine.
if you want to change htdocs dir in apache you need to change the following in httpd.conf:
DocumentRoot "c:/apache/htdocs"
the directory directive
<Directory "c:/apache/htdocs">