Using SIP: A Few Reasons

Below is a recap of a few journal entries outlining a few reasons why i believe one might be compelled to make use of SIP:

1) A layman's introduction to SIP
2) Interoperability
3) Gizmo is cool
4) Phone 2.0

The fourth one "Phone 2.0" shows how I'm able to use the same account to place calling card calls over a traditional 1 800 number programmed into my cell phone, on-top of using my computer to make calls through the exact same account, over SIP this time. In neither case, do i ever have to type-in my calling-card information: On the cell phone, it's programmed-in, it sends the tones for me. On the computer, it's baked-in the SIP authentication credentials.

Here's a little bit of Math:

- my Sprint "Simple 7" long distance service costs me $2/month and calls cost me 7 cents per minute anytime. I still can't call France using this long distance service, without paying out my ears.

- iconnecthere.com lets me make calls for 3 cents a minute anywhere in the U.S., anytime, with no recurring fees. Calling France is about 6 cents a minute.

- Gizmo Project lets me make calls for under 2 cents a minute anywhere in the U.S., anytime, with no recurring fees. Calling France is about 5 cents a minute.

The only reason why I stuck with long distance service until now was because of the past inconvenience of using cheaper services. Now that i call through the computer for cheaper and more conveniently, Sprint is about to go bye-bye, as soon as the dbt-120 and the hs810 arrive here for Brandy's iBook.

So recap, to reach cheap communications Nirvana, i'm looking for:

1) a good global traditional calling card account, that lets me use worldwide toll-free numbers to make calls, through traditional phone.
2) the same account needs to be tied to a SIP interface, so i can leverage it to make calls from any SIP-enabled computer, or device. Such "device" might for example be a hybrid SIP/GSM/3G phone, an ATA, an asterisk box.
3) the same account would ideally also provide me with an easy-to-remember/use SIP address: username@someprovider.com so people may call me for free.
4) the same account would allow me to purchase a phone number in the area code I want, which i might advertise as my "mobile" or "global" phone number. This number would be tied to the incoming SIP interface defined in 3).

that'd all be a pretty good start. What i have so far is pretty good. In all cases you've gotta distinguish services that have recurring costs associated with them, such as Vonage, and services that let you "pay as you go" by putting money into an account, where "per minute rates" make more sense to me, as they really reflect what I'm paying.