New Macs that have Leopard are equipped well in the web department. You can start Apache up pretty easily if it’s not already running. First, find out if it’s running or not. You can do this by taking a quick peak at localhost. If your browser does not yell at you for going to a place does that not exist, you’re probably already running Apache.
However, lets say you do need to start it up. You can by going to System Preferences > Sharing. Look for Web Sharing. Under that header you should see Start Web Sharing, click that. Then you should be good to go. To fire it up, head over to localhost again and if you’re lucky, you should get a page telling you about Apache or that you’re not allowed to view the page (which is fine, if you’re just going to the index and there is not one yet.)
Sorry for the lack of pictures. Today I wanted to do this in my computer class to quickly test something out in PHP. I was about to run my code and then I found out that apache was not running. I attempted to turn it on, but of course, it’s disabled for Students. (Better luck next time.)