Race Dates

I have just started training for my first tri. However, I have not yet found a race to compete in! What's the best, and most complete source to find a list of races in the US. I live in MN, but will travel anywhere in the US to race. It's getting chillyup here, so there won't be anything until next spring in my area. I want to train for something around the Feb-April time. Any thoughts on a great beginner race? Thanks!