What I know is, warrants are like options, but they are written/ issued by institutions, such as banks. For example DeutscheBank. Sometimes the company itself might issue the warrant, for instance GOOG might issue warrants on itself.
But the thing about warrants, when compared to options, usually they have much lower effective gearing, and the secondary market is more illiquid. Furthermore, you cannot write, just buy or sell back. And choices are more limited, usually just Near The Money ones.
If you want to find a warrant on GOOG for example, it might be issued by multiple insitutions so you must hunt and see which one is better.
I haven't been able to compare deeper, but Im sure warrants have other differences and other defects when compared to standard options.
For online quotes, try
www.dbwarrants.com. This one is from DeutscheBank.
And
www.gs.com/client_services/trading_capital_markets/warrants/index.html This one is from Goldman Sachs.