it's dominated by the weak php developers you speak of, but if you just filter everybody out who charges less than $20 per hour[1], you'll get rid of most of them and be left with some good people.
after you've gotten a few hundred proposals on elance it will be tempting to just ignore everybody from certain countries. i urge you not to do that though. instead filter by hourly rate. an indian or pakistani developer charging $25+/hour is either delusional or really, really good (i.e. $150+/hour if they were in san francisco). a quick skype chat is usually sufficient to figure out which.
[1]do this yourself, don't set the terms to $20/hour, or all of the bad devs will just try to charge you $20/hour. by setting it to 'not sure' it's a race to the bottom and all those guys will be competing with each other for the lowest hourly rate. you then just ignore all of them.
