Well, that's a little misleading. There's nothing illegal about BUYING Canadian services, but it's illegal for them to SELL it. So you have to jump though a few hoops.
Google ("Address Broker" Starchoice) for some info.
Some people seem to think address brokering is illegal, so if you're concerned, you might want to do some research on "falsifying addresses". But those brokers have been in business a long time. You pay them, they rent you a PO Box, and they pay your bills for you. I don't see a problem with it, not even from an ethical standpoint. (And I have reletively high ethical standards.) Especially if you also subscribe to a US service.