I work and live in the US. However, on a side, I do some occasional work for two science editing companies that are located in Ireland and UK. How do I file this?

[IreneS]

Did you travel to Ireland/UK in order to do this work?

[petchev]

No, I do not travel to these countries. Thank you for your help. I got my answer from TurboTax

[IreneS]

Treat the income just as you would for a US-based client.  Your work for the foreign clients doesn't qualify for the foreign earned income exclusion since you didn't work and reside outside the U.S.

If these companies withheld taxes, you can enter that information for the foreign tax credit.

To enter foreign taxes paid, please follow these steps:

1. Click on Federal [Personal in TurboTax Self-Employed] > Deductions & Credits.
2. In the Estimates and Other Taxes Paid section, click on the Start/Revisit box next to Foreign Taxes. 
3. On the Foreign Tax Credit screen, click on the Yes box. 
4. Continue through the screens, entering the requested information.