Don't expect a
valid legal answer from anyone unless he or she is a IRS qualified rep or a qualified CPA! You might get 1000's of answers, but will have no validity in the eyes of the IRS.
Whatever you do, talk to your CPA (that is also tax deductable) I can tell you what happened to me or how I did my taxes, but that will/might not be valid for you. The best is to research your case at
http://www.irs.gov/
or what I did, buy the latest of the following 2 books
Doing Business tax-free by Robert A. Cooke and
422 Tax Deductions for business and self emplyed individuals by Bernard B. Kamaroff
These books are extremely helpful and no business owner should be without them!