The basic process of the Norbert Gambit is to buy an interlisted stock on one exchange, and then sell it on another exchange. You see, some stocks are listed on both a Canadian and American exchange. Examples, include Research in Motion (ticker symbol RIM in Canada, RIMM in the US) and Potash (ticker symbol POT in both Canada and the US).
The process has been described a number of times already, so I have linked to those more detailed descriptions below. If in doubt, call your brokerage first and explain to them what you are planning to do.
Tip - In order to complete the process, most brokerages require you to phone them to move the stock from the CAD side to the US side (or vice versa).
More recently, a company called Horizons BetaPro has started offering two US Dollar Currency ETFs - one trades in Canadian dollars and the other in US dollars. Similar to Norbert's Gambit, you can buy one on the CAD side of your account and then move it to the US side to sell it (or vice versa). Using these two ETFs is inherently less risky than an interlisted stock. A more detailed description of the process can be found here:
Easy Norbert Gambit in TD Waterhouse RRSP Accounts - Canadian Capitalist
Norbert's Gambit: A better way to buy U.S. dollars - MoneySense
Low Cost Currency Conversion with DLR/DLR.U ETF - Million Dollar Journey
US Dollar Conversion >