Some good ideas from TLD's General Counsel Blog:
A buy-sell agreement is one option (which won't be discussed here in this post) and setting up an estate plan is another option often considered. If you set up an estate plan to include a revocable living trust, you can assign or transfer your business interest into your trust and specify what happens to that share of the business interest.
One common approach for married couples is to transfer the business interest to the trust and allow the surviving spouse to manage the interest and upon the death of both spouses, the interest is then transferred to the surviving children either in equal shares or to the child who is most interested in the business interest (for whatever reason). Additional language can be included depending on the type of business interest involved and what your wishes are in case something happens.
If you have an Indiana business and need legal counsel for estate planning, I am taking on new clients at this time.