If you are not an S corp it is disregarded entity and you file it on Schedule C in your personal return.
You need to fill out schedule C for self employment business income and pay self employment tax in addition to regular income tax on it. The SE tax is to pay Social Security and Medicare tax that wasn't taken out like on a W2.
You use your own name and ssn or business name and EIN if you have one. You should say you use the Cash Accounting Method and all income is at risk. After you put in your income and expenses if your net profit is $400 or more you will pay 15.3% for 2013 Self Employment tax in addition to your regular income tax. The Schedule SE will be automatically filled out for it.
Here is some IRS reading material……
IRS information on Self Employment
http://www.irs.gov/Businesses/Small-Businesses-&-Self-Employed/Self-Employed-Individuals-Tax-Center
Pulication 334, Tax Guide for Small Business
http://www.irs.gov/pub/irs-pdf/p334.pdf
Publication 535 Business Expenses
http://www.irs.gov/pub/irs-pdf/p535.pdf
Fill out Schedule C here
The Business Tab - Continue
I'll choose what I work on
Business Income and Expenses
Then….
Profit or Loss from Business, click Start or Update
You don't pay yourself or enter a salary or withdrawal for yourself. All the business income and expenses are your personal income and expenses in the first place. You just fill out a Schedule C. The net profit or loss is your income. If you have a net profit of $400 or more on schedule C you will pay SE self employment tax on it in addition to your regular income tax. It's all included on your personal 1040 form.
