Having recently stumbled upon Jrim's Proxy Multiply, it's now my go-to tool for grabbing some quick free proxies. I just hit the "Get proxies!" button and within an hour or two I've got 3,000 tested working proxies.
And if you need some site-specific proxies, it can do that too. Just follow these steps:
- open the Configure menu
- go to HTTP Proxy Testing
- check Check proxies against a specific url and click configure
- in the dialog that opens, put the homepage (http://www.manta.com, http://www.yelp.com, etc) in the Url to Navigate to textfield
- in the Content to look for in the page you want to put any text that will always show up on a page (I like to use the google-analytics id)