TD Waterhouse provides Level II data with their "Active Trader" platform, but you are looking at a fairly hefty monthly charge.

For US stocks you might want to take a look at the BATS website. They have a page which provides (for free) real time bid/ask details for a couple of stocks at a time: http://www.batstrading.com/data/book...

And if you hit the "spawn" icon, you can open up multiple tabs each of which could be pointed at one of you favourite stocks.