Google Finance does let you retrieve up to 100 stock quotes at once using the following URL:
www.google.com/finance/info?infotype=infoquoteall&q=[ticker1],[ticker2],...,[tickern]
For example:
www.google.com/finance/info?infotype=infoquoteall&q=C,JPM,AIG
Someone has deciphered the available fields here:
http://qsb-mac.googlecode.com/svn/trunk/Vermilion/Modules/StockQuoter/StockQuoter.py
The current price ("l") is real-time and the delay is on par with Yahoo Finance. There are a few quirks you should be aware of. A handful of stocks require an exchange prefix. For example, if you query "BTIM", you'll get a "Bad Request" error but "AMEX:BTIM" works. A few stocks don't work even with the exchange prefix. For example, querying "FTWRD" and "NASDAQ:FTWRD" both generate "Bad Request" errors even though Google Finance does have information for this NASDAQ stock.
The "el" field, if present, tells you the current pre-market or after-hours price.