Thanks for the suggestion Medusa. I don't have a vet so what should I look for in an establishment? What types of test will they do and when will I know the results?

I hope it's not serious but it just worries me since he's never barfed twice in one day before. Yes, he vomits soild food, not liquids, and he usually does it within 5 minutes after the meal. I also notice he's drinking more water now than during colder weather. I did some research on the net and some people say it's okay for a cat to barf once or twice a week, is this true?