Larry Ullman wrote a great post about his experience with MAMP. Many years before I heard about MAMP I had been using XAMPP (http://www.apachefriends.org/en/xampp.html), it was in fact that a friend told me about the great piece of software he was using called MAMP which was only $39 (at the time, today you have to pay $59 for a new version and $29 for an upgrade). MAMP is able to let my friend have a LAMP stack up and running in no time in his MAC. I asked my friend why would he be paying $39 for MAMP while XAMPP was free! and he had two reasons. One, he could update the vhosts quickly, second he had been using the software for quite a while so he didn't have to learn a new piece of software. I believe there is a free version but you are not able to edit the vhosts which for what I undrestand is one of the main sell point for many.

My setup for PHP development on MAC and PC is the free XAMPP package. Since I use the MAC 99% of the time I have created an alias in my .bash_script which opens two files in TextMate that allow me to create a vhost rather quickly. Lastly I open the XAMPP control panel, restart Apache, and I am set to go.

here is my .bash_script alias:
alias vhosts="mate /Applications/XAMPP/xamppfiles/etc/extra/httpd-vhosts.conf mate /etc/hosts"

There are other benefits with XAMPP (it may be very similar with MAMP but I have never used it) after you start mySQL from XAMPP control panel you can do all your database administration by visiting http://localhost/phpmyadmin. I have also set up a "dump" alias http://dump.localhost where I can drop any quick php tests without having to create a new virtual host.

http://dump.localhost/test_a

http://dump.localhost/test_b

http://dump.localhost/test_c

Code

If you have made changes to the httpd.conf file do not restart your server right away but rather run the configtest command that will provide valuable information on what errors there may be in your configuration of any.