Any college that has a theatre program will offer singing and acting classes. It depends on what type of singing/acting you are looking for. There are programs that prepare students for theatre, film, or a combination of both. Also, depending on your singing style, you might want to go classical (opera) or contemporary (for Broadway or radio).
It also depends on where you'd like to study. Many theatre and acting programs are located in New York and L.A., but there are many other programs located throughout the country that will also help you launch your performing career. Take a look at our directory of schools--good luck!