i started with my own stuff, then stuff for friends and family, then they told people. and some organizations i'm a part of needed help and i did stuff for them.
also, i just picked up a freelance php job while cruising on a forum for an open source product i'm using for a site i'm developing. that guy then told his brother who just contacted me with another freelance request. so i would find an app that people use, learn it, and then cruise the net, forums, ask around if people need help with it.
i wouldn't waste my time with asp. java is tough to break into, i've tried.
it's a cliche, but it's all about networking. which is nice since i'm a Network Engineer by day. i've never even gotten one bite from monster.com in 2 years.
it just grows organically. it's been impossible for me to get freelance jobs through freelance bid sites or job/career sites. and actual salaried php jobs with actual companies seem non-existent.
i love php but i don't think it's mature enough to be embraced by mainstream companies. it still has the (erroneous and unfortunate) stigma of something for 14 yr old kids.