Another variant using Skype is their online number service (formerly called “SkypeIn”). Unlike Skype's regular voice-over-IP service, there is a monthly fee but there are several advantages:

• Overall costs are still reasonable compared to traditional long-distance/international calls
• It's completely transparent to the caller, they just call something that looks like a regular local/national number, no computer is involved
• You pay for it, depending on their subscription it might even be completely free to them

Another variant using Skype is their SkypeNumber or online number service (formerly called “SkypeIn”). Unlike Skype's regular voice-over-IP service, there is a monthly fee but there are several advantages:

• Overall costs are still reasonable compared to traditional long-distance/international calls
• It's completely transparent to the caller, they just call something that looks like a regular local/national number, no computer is involved
• You pay for it, depending on their phone contract it might even be completely free to them

Caveat: The terms of use are (probably deliberately) vague on potential residency requirements. In some places, it might conceivably be illegal to get a number without living there. I assume being able to provide a US address or US credit card would be enough in practice, if even necessary (I personally never tried to get a number in the US).