I guess there was a high demand from Spanish speaking users for PhoneTag but Mexico seems to be first. PhoneTag has just announced that their Spanish visual voicemail service is now available in Mexico along with the US, Canada, & Australia.
You can sign up for the new Spanish service at www.phonetag.com/es
Sadly since the service requires you to forward your cellphone number you can’t really use it in unsupported countries. This is because the international forwarding costs would probably be prohibitively expensive. Hopefully PhoneTag will be adding more forwarding numbers in different countries soon.