The 'Watch' (stock watch list) tab of my site uses YQL finance:
http://momoneyalerts.com/mmalite/
Frequently getting this result for queries like the one below for the last few weeks (even today - Sun):
{"query":{"count":0,"created":"2013-03-24T21:04:40Z","lang":"en-US","results":null}}
http://query.yahooapis.com/v1/public/yql?q=select%20Symbol,LastTradePriceOnly,Change,PercentChange,Volume,AverageDailyVolume,LastTradeTime,LastTradeDate%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22YHOO%22%2C%22AAPL%22%2C%22GOOG%22%2C%22MSFT%22%2C%22VPHM%22%2C%22AH%22)%0A%09%09&env=http%3A%2F%2Fdatatables.org%2Falltables.env&format=json