You need to report any income--either as "misc. income" or on Schedule C as self-employed. The litmus test for which it is is "Are you pursuing this as a hobby or a business?" If it is a business, you may have some deductions for travel, etc., that you don't have if it is a hobby, but you will also have to pay self-employment tax. You can have both a hobby AND a business if you have more than one source of extra income.
