Your freelance income is self-employment income. You are required to report all self-employment income on SCH C as a part of your personal 1040 tax return. In addition to regular taxes, if you have more than $400 of SE income, that self-employment income is also subject to the additional self-employment tax of 15.3%.
"This exclusion probably doesnt apply to investment income does it?"
Depends on the type of investment income. There are to many possibilities to cover here. But if you paid foreign taxes on that income, then the IRS gives you a credit for those foreign taxes paid.
