Solid advice from riverripper, +1. I'm a budding entrepreneur myself and I completely agree with what he said. The rankings are pretty meaningless when it comes to "learning" something like entrepreneurship.
Virtually any business school worth its salt will give you the classes, clubs and business plan competitions you need to refine your entrepreneurial goals. But in the end it's all about the network. For instance, I already have a very strong professional network within my industry of interest in New York City - so Columbia, NYU and Cornell even though they aren't specifically known for specialties in entrepreneurship are probably the schools that make the most sense for me. If for nothing else then because they give me the most opportunities to maintain and build upon my professional network in New York.
Furthermore, if your business plans don't involve tech or "products", then it's not even a requirement to get access to venture capital. You should just have lots of potential clients who are familiar with what you have to offer, and you can start out small. Of course an MBA can help you figure all this out, but it doesn't need to be from the school ranked #1 in Entrepreneurship.
These specialty rankings are usually completely arbitrary anyway. Look at the schools ranked highest in "International Business."