Your profile says you're in Canada...you should be able to run a business name search online in your province to see if anyone has registered the desired name. There are various fees depending on the report you want. (I would search by search engine first, it may save you money!)
In case you're in Ontario:
Business Name Search
As the others have said, check to see the domain name is available before you go ahead and register the name. If you're in Canada, you may want to consider the .ca domain extension in addition to the .com one.