ptysef

I use VoIP already in Thailand. Not with US but Germany. I bought in Germany a DSL modem which can connect to DSL stand-alone, there is no need the computer running. Further I can connect normal telefones to the modem. I made contract with a VoIP provider in Germany so I got a local number in Germany. Everybody can call this local number in Germany and here in Thailand the telefone is ringing. In my case everything works perfect.

Yes! Look my link above, TOT has the same for THB 700,- (+ tax)! And reporting from real life, TOT will work stable, but TT&T has very often failures, sometimes several days! That's my experience and those of my friends here.

Yes, you can. E.g. at the TuckCom, South Pattaya Road, corner Soi Day&Night.

I have DSL from TOT. Sometimes it is fast, sometimes slow (especially between 16:00 and 23:00). The offer can be found here: DSL TOT. I would advice the 512/256 kbs line for 700 Baht a month (flatrate) as the abroad internet addresses can not be connected faster than ca. 385 kbs. But the connection is very stable, in more than 7 months I had only 1 fallout (nationwide) for 4 hours. After applying you will get it after ca. 1 week. If you want use VoIP, there are better dsl modems available in Europe than in TH. This comes from as the CAT has the monopol over all outcounty calls. But you have to take care that the modem can handle Annex-A or can be patched to it, as in some countries (e.g. Germany) there are only Annex-B modems offered. Annex-B will not work in Thailand.