Skype over 3G mobile phone

[tycho]

I know that you can get Skype on the pocket pc but I may be in line for a job where I may have to call the States quite a lot.

My question is, how much data does Skype use per minute of conversation? My data costs £2.35 per Mb over a 3G connection so if the calls cost £1 per min to the US, it would be cost effective if Skype lets you talk for 3 mins for £2.35.