My wife is attending the TechMunch conference in Boston. I do her accounting, so my first instinct was: how do I file this expense? :-) After some Googling, I found this very useful Motley Fool blog post about filing small business expenses. I learned that such training (aka professional development) expenses don't have a pre-defined category and can be listed as miscellaneous expenses on the second page. The post explains in English what expenses belong in each of the major categories listed on 1040 Schedule C. In addition to the main post, there are many questions and answers in the comments for edge-cases like my issue. It seems like an excellent tax time resource.