How successful are lead generator businesses and how can I create a business plan for this?

There are many lead generation networking groups available (Business Network International, www.bni.com, for example) that may be a good place to start. Most operate as non-profit, member-driven organizations, but it will still give you a good place to start. The nature of leads that are exchanged and the method they use to track results may be helpful for you as background research.

While your business will be unique and likely have some elements that are not typically associated with a traditional business model, you're business plan will still follow the same general format as most others. You may find looking over some of the 500 sample plans helpful. You may also want to review some of the How-To resources here.