
I’m working with some old code that needs to run PHP4… on my desktop machine I was able to throw it into MAMP and just check the PHP4 option, but our dev environment on Dreamhost is PHP5-only… that is to say, you don’t get to choose PHP4 or PHP5 when setting up a new host.
However, the DreamHost wiki has a pretty slick shell script that will download & compile PHP4 as a CGI executable… and with a little tweaking to some of the install paths there’s no reason this shouldn’t work for pretty much any environment: