In 2005, I worked primarily as an independent contractor, for several small companies and non-profits. Two of them were for over $600 and sent me 1099s, but three of them were under $600 jobs and didn't send me anything. Am I obligated to report these three? (I'm imagining the answer is yes, but I wanted to confirm that just because I didn't get a form for each of them doesn't mean they're not reporting them, right? One of them has my social security number and I filled out an employment form, but the other two I filled out nothing and they know no tax revelevent information beyond my name, address, and phone number.) Where would I report this income on a 1040? (I looked through it and was confused.) Also, a couple of the checks have "Reimbursement for Expenses" written in the memo section of them. Do I have to report this as income or anywhere else on my taxes? Thank you.

You are required to report any income received, whether it was reported to the IRS or not.

I would fill out a Schedule C as a sole proprietor and list the income and expenses related to this work, bith 1099 and non 1099. Travel time, consumables used and many other items can be listed as expenses to reduce the taxable amount of the income.

ScottGem has it right!