@Prinec: Accent or no accent, there is a probation period where the employer decides if he can understand and communicate well with the employee or not.
I totally agree that accents do become a major problem when it comes to communication. Personally, I am a Canadian immigrant and many people don't even realize that English isn't my first language. I am a Palestinian (Arabic is my first language) and I have been working for more than 5 years dealing with customers on the phone and in meetings without people having difficulty understanding me or communicating me in general.
My point is, no all immigrants do have a horrible accent and can cause communication problems. Hire them, then decide if they will be an issue.