The income your husband receives as an employee (reportable on W2 form) should not be mixed with self-employment income.
It doesn't matter from tax purposes how the business would be organized - solo proprietorship, DBA, LLC or partnership - for tax purposes all these are disregarded entity and the income and expenses should be reported on his personal tax return.
You will use schedule C for your self-employment income and expenses - http://www.irs.gov/pub/irs-pdf/f1040sc.pdf and calculate your net income. You net income from self-employment is a subject for 15.3% self-employment taxes and should be calculated on schedule SE - http://www.irs.gov/pub/irs-pdf/f1040sse.pdf
You will use 1040 form - http://www.irs.gov/pub/irs-pdf/f1040.pdf for your tax return - following would be important entries:
line 64 - federal income tax withheld from Forms W-2 box 2 and 1099misc box 4 (if any)
The key point is to determine qualified business expenses and to keep a good record.