[Astronomy_Domine]

Hello, everyone!
This is my first post here.
Right now I have a regular phone.
I'm thinking about buying a pda-phone.

Major reason - to use it for VoIP (my cellphone-to-someone's computer VoIP calls (Skype for example), international VoIP phone-to-phone calls).

Minor use - emails, some browsing, youtube perhaps.

My questions are:

1. Which cellular carrier in US has fast internet, capable of working with VoIP?
Which carriers (if any) do NOT block VoIP?
I've heard AT&T blocks VoIP, Is it true? How about Sprint, T-Mobile, Verizon and others?

2. Which Windows Mobile software is the best for VoIP? Are there any VoIP options for iPhone? I need something that can make free phone-to-computer calls as well as paid phone-to-phone (like Skype).

3. Which software has lowest requirements on the internet connection speed?

4. Is it possible to make VoIP phone calls over GPRS, EDGE. They are faster then dial-up and I used to have good experience with Skype over dial-up during 50+ kbit/s connections. Or is 3G a must-have requirement for VoIP?

5. And finally which Phone is the best for VoIP? Which works flawlessly, able to use same regular speaker that you use for regular phone calls (instead of loud speaker or headset , though headset is ok too), has less issues? Whould be nice if that phone had a large 800x480 screen (but 640x480 is ok too especially if it's more reliable and works with VoIP better without issues).



I would appreciate any help to shed some light on the above questions. I did some research online , but info is controversial.

Thanks