$ sudo port install apache2
Password:
--->  Fetching pcre
--->  Attempting to fetch pcre-7.7.tar.bz2 from ftp://ftp.fu-berlin.de/unix/misc/pcre/
--->  Verifying checksum(s) for pcre
--->  Extracting pcre
--->  Configuring pcre
--->  Building pcre with target all
--->  Staging pcre into destroot
--->  Installing pcre 7.7_0
--->  Activating pcre 7.7_0
--->  Cleaning pcre
--->  Fetching apache2
--->  Attempting to fetch httpd-2.2.9.tar.bz2 from http://www.apache.org/dist/httpd
--->  Verifying checksum(s) for apache2
--->  Extracting apache2
--->  Configuring apache2
--->  Building apache2 with target all
--->  Staging apache2 into destroot
--->  Creating launchd control script
###########################################################
# A startup item has been generated that will aid in
# starting apache2 with launchd. It is disabled
# by default. Execute the following command to start it,
# and to cause it to launch at startup:
#
# sudo launchctl load -w /Library/LaunchDaemons/org.macports.apache2.plist
###########################################################
Warning: apache2 requests to install files outside the common directory structure!
--->  Installing apache2 2.2.9_1+darwin_9
--->  Activating apache2 2.2.9_1+darwin_9
--->  Cleaning apache2

メッセージにある通り、自動起動を設定。

$ sudo launchctl load -w /Library/LaunchDaemons/org.macports.apache2.plist

httpd.confを添付されているサンプルからコピーする。

$ sudo cp /opt/local/apache2/conf/httpd.conf.sample /opt/local/apache2/conf/httpd.conf

apachectlなどへのパスを通すため、.bash_profileなどで$PATHに
/opt/local/apache2/bin
を追加しておく。