Skype alternative for older PCs -- do any exist?

[jakobkraft1]

My wife would like to chat with family in India, has what I think is a good webcam (Philips 900NC) but her desktop PC is only an e-Machine with an Intel Celeron D Processor 330 which, despite having 768 kbps DSL, is way below what Skype recommends for video calls (CoreDuo only, apparently).
Her mother in India has a slightly faster P4 3.0 HT desktop, but still is not quite the same as CoreDuo - so I'm wondering is there any kind of video calling service or software that will work with these older machines...?

Thanks in advance...!

 

[CSMR]

Has she tried it? I'd be surprised if those machines weren't fast enough.

 

[CSMR]

You can make video calls with any of the main IM services.