How can you use Twitter for business? Here is my suggestion, use it to brand yourself as an expert or important contributor to some field. Whatever you are good at, write about it.
Then try to follow anyone who has similar interests. They will follow you as well and you will begin to build an online community.
It takes an effort to post meaningful thoughts and ideas everyday, but consider that your posts only appear for a short while. It is a way to connect with business associates.