Hi

I use AT&T Business Internet Services: http://www.attglobal.net/
They've got POPs almost everywhere and they support international roaming - not
the cheapest though, but I've used them for about 2 years now and have not had
one evening down in that time, not bad.

BTW, I used their recommended Linux setup scripts as a base to config pppd,
no mess, no fuss, just works(tm)

Oh, I use them from South Africa, so YMMV :-)

--et