If I established a LLC and a C Corp in 2008 but never did any business through these entities, do I still have to send in tax forms? There was no income and no expenses. If so, what forms for each?

Yes, you must file tax returns. You will also pay minimum franchise fee every year.

An LLC can be a sole proprietorship, partnership or a corporation, so the tax form will depend upon the entity.

For C Corp, you will file Form 1120, then state return and then corporation return where the corporation is registered.

Yes, you must file tax returns. You will also pay minimum franchise fee every year.

An LLC can be a sole proprietorship, partnership or a corporation, so the tax form will depend upon the entity.

For C Corp, you will file Form 1120, then state return and then corporation return where the corporation is registered.

If I filed a Form 4868, Application for extension. With my 1040 does that cover for the 1120 and the LLC as well? If not, is there a penalty if the 1120 for the C Corp or Schedule C for the LLC, if neither entity has an income or expenses?

C corporation return Form 1120 has nothing to do with your individual return. Due date was March 15, 2009.