Are "international" SIMS becoming obsolete?

[snidely]

DR -
I agree that wifi (be it UMA, Skype, etc.) is best used for outgoing. I use BB email for incoming. It is a lot cheaper getting/sending email via BB (less than $1/day for unlimited email) than the cost of someone sending SMS to you or you sending SMS out.

When recently in Zambia, I could get BB email at a place along the Zambezi that had satellite internet. It was too slow and too much latency for a reliable UMA voice call. When connected, the voice quality was almost useless. The service, I was told, wasn't cheap. You pay the internet service provider by the mb. The cell system did not have BB service. There is cell service in areas that don't have electricity.
If I could have connected via UMA it probably would have used up a lot of the guys expensive data pkg.

If the E61 can make use of Skype as easily as you can use it on a computer - why don't more people roam that way? IF I read the Skype blogs correctly, it appears that an app. for BB's is on the way. Is using Skype on the E61 as easy as making a regular cell call?
I have never used Skype Out - which is what would be needed to make the app. useful on a cell phone.
It will be interesting to see what G does w. Google Voice. I have two G numbers, but only use them so I can have a local number in Miami to give out and one to use as an additional number to give out in the Bay Area. I gave up my landline a year ago and tsfrd. my 35 y.o. number to my TM cell.

...mike

[hkr]

UMA is an interesting techology, but I have not been able to try it. Can someone please advise a link to a list of providers who support UMA?

However, I believe in protocols that are open to anyone: SIP allows anyone to start their own service, interface whatever with whatever... This helps keeping end-user prices down as there will always be fierce competition, whereas with UMA you are bound to your own mobile provider.

What I see as a major problem with wifi SIP roaming is that free wifi hotspots are not that easy to find, and even if you find them, they might not work properly with SIP. They allow web browsing, some allow POP3 or IMAP mail retrieval. Some SIP providers therefore allow connection using TCP rather than UDP, and on ports like 80 (normally used by http)... Problem is sometimes not firewals, but multiple NAT-ting and other problems. I have never tried to use SIP via VPN, but I have heard people say that it can often help.

However, I see that many people now use Skype and other VoIP software on their laptops for making calls while abroad. Using their phones for this is not yet that frequent. It is partly because a relatively small portion of phones available today offer wifi and voip, and those that do are relatively expensive.