Well, it is not that simple. You can deduct as a charitable donation itemized deduction, certain expenses paid for a student living with you. The rules are extensive and there are certain items that you have to file with your return (meaning that you will have to file it by mail). The maximum deduction is $50 for any whole month that the student lived with you.
To read the requirements and the info on what you can count as expenses, start on Page 4 of IRS Publication 526, at this link:
http://www.irs.gov/pub/irs-pdf/p526.pdf
The instructions on what records have to be filed with your tax return are on Page 20 of Pub. 526.
I've read a lot indicating that it depends on the situation, and even the tax publications lead me to the same place. If the student is attending a public government program, then you can not deduct expenses, it is not a business, etc. However, many people host through third-party programs, for international students who attend private schools. This is a whole other animal, and I'd like to see more research here about that. All I have researched has led me to the same place that it WAS intended to earn money, that it IS a business, there is a contractual service being provided, therefore, in all forms, a business arrangement, and business income and related expenses. These providers receive a 1099 and are responsible for expenses of room setup, technology support, meals, etc. Can anyone speak to this?