Replying to [duddles]:
When registering/incorperating a business, underscores in the name will usually make it a non-distinguishable name and thus are not accepted. As far as numbers and letters they must consist of letters in the Roman alphabet, Arabic numerals (0, 1, 2, 3, etc.). If its a internet based business numbers are not all that uncommon but you will hardly ever find a proffesional business with a domain name that will include a underscore. I wouldn't recomend staying away from all business names that have unusual characters because it may simply be a error made when listing by a person foreign to english text. I would definatly investigate further to make sure they are legit outside of the name. Keep in mind im only talking about US law, perhaps in other countries the rules for business names are different. Can anyone else confirm this? I hope this helps you.