I have tried 1broker but it isn't working. Any suggestions as to where I can trade bitcoin with leverage? Thanks
The only site that comes to mind for me when you ask about this is definitely kraken, so I would recommend you go and see whether or not that suits your needs.
I thought there were some other exchanges, but looking through the thread apparently poloniex doesn't allow for BTC/USD leverage so that's something to write off, unless you're leveraging alts.