This is a gray area if not illegal. You would have to find a program broker to go through which would set you up with a Canadian address in order to be able to provide you the service for a fee. You pay the broker and the broker takes care of the rest.
Its a fairly simple process to do, I finished my setup today actually.
While my Dish network system was being installed, I climbed up on my roof and installed my Starchoice dish in its final resting spot. (good thing the installer is a friend of mine )
Made a call, a few emails, and a few hours later, I am surfing along with Starchoice
Now if its technically legal, probably not, however Starchoice wont turn away a paying customer. Bell ExpressVu apparently is a little more anal about things (specifically having the modem connected for dial-to-mom connections), but Starchoice does not really care... (actually, the DSR205 does not even HAVE a modem in it)
It's not illegal, as there are NO laws in the U.S. against subscribing to a foreign provider. In fact, the 1st amendment would ban such laws. On the other hand, the providers do need agreements with copyright holders to sell the progamming in the States. So Bell and Starchoice are mostly blocked from selling openly in the States by not having licensing agreements with the copyright holders.
But there are no laws that can punish an American from subscribing. So it's basically a very light shade of gray
Bell and/or Starchoice could be open to lawsuits from copyright holders if they "knowingly" sell in the States. Which is why Bell/StarChoice shuts off a signal if someone pretty much says "I'm in the States", because then they have probable cause, and are open to a lawsuit. Otherwise they turn a blind eye.
btw, the reverse in not true in Canada. There is an actual law making it illegal to subscribe to a foreign service. No 1st amendment up there.