I do quite a bit of web development, and I like to run virtual hosts of my production web sites locally, makes for an excellent, develop/test/release cycle and I can work anywhere (even on a plane). To do this I setup some virtual hosts on my Apache server called dev.domain.com, e.g. dev.sinclair.org.au which points to 127.0.0.1 and then in the apache config I setup virtual hosts pointing to those server names, and wallah. Below is a little more detail on getting this setup on my new MacBook Pro running Leopard OSX.