If you will be working in an English-speaking work environment, you will find there is no great need to learn Dutch. However, if you really want to get to know the country or if you plan to stay for a longer period of time, it is useful to learn the language.
Most Dutch people speak English fairly well and will be happy to speak English with you. In the Netherlands, television and films are broadcasted in their original language (many of which are English spoken), with Dutch subtitles. Therefore, there is no real need to learn Dutch to get by. But really getting to know the country, its culture and society will, of course, go easier if you have a (basic) understanding of the local language. Speaking and understanding a Dutch will make everyday activities easier too: grocery shopping, going to a restaurant or following the news.
There are Dutch language courses available for basic language skills as well as more advanced courses. Students need to be able to speak English, which is usually the language of instruction. Entering a course may require you to do a placement test or to have an intake interview with a teacher, depending on your situation.
Several organisations offer Dutch language courses:
If you want to start learning the basics at your own pace, you could start with online courses:
In Utrecht, you'll find many (free) groups and activities, where you can practise Dutch at all levels: