Since you have an ATT iPhone, see if you are eligible for a foundation account (using through your school, parents, relative, etc). There is an iPhone International plan (one year commitment) that gives you unlimited 3g in most countries. This is only available on certain FAN accounts and folks on the retail side of ATT don't know about it. Check out this thread:

http://forums.wireless.att.com/cng/b...hread.id=87133

Many iPhone VOIP apps will now work over 3g. When you get a solid 3g signal in your port of call, find a place to sit, and call home. VOIP over 3g works best when you are stationary.

Now, get a cheap quadband GSM phone and get an Ekit Prepaid Passport SIM:

http://www.telestial.com/view_produc...T_ID=MSIM-PP02

It gives you cheap prepaid in many ports of call. You can beat the $0.19 a minute inbound rate to their US number if you find a cheap calling card for UK mobile numbers. Inbound calls to the UK number are free in many of your ports of call.

Lastly, get a Google Voice number and hard (unconditionally) forward your cell to it. You'll get visual voicemail over the net, free SMS to/from the US. You'll also get a so-so transcription of the voicemail message.

It will take some fighting, but you should be able to get it. If this doesn't work, early terminate and go to Verizon. They have a Blackberry International plan for about the same that includes cruise ship roaming.

Keep your usage low, but look at tether.com. I might also consider a web compression scheme such as http://www.propel.com/technology/index.html.