If you are in Canada, best way is to go your local bank, get a merchant number, goto Global Payment Systems, set up a processor account then head over to Soltrus for Verisign Payflow to securely process credit cards.
In the states, you can find merchant solutions a dime a dozen.
Paynet Merchant Solutions is one. Take a look at them. They do their business with Harris Bank and can get you rolling in about 2-3 weeks depending on your business status, etc. Charge around $500-$600 for the complete solution (Startup).