Morodo (and its rates)
 

A few days ago I noticed a Google Ad of http://www.morodo.co.uk - as I understand it's a callback phone application + some prepaid service behind. There are two version MO-Call Home (Home=UK, of course :-)) and MO-Call Roaming.

Checked the rates to UK...

Call from Poland Mobile to UK
To UK Mobile O2 37 pence/min
To UK Mobile Orange 37 pence/min
To UK Mobile T-Mobile 37 pence/min
To UK Mobile Hutchison 3G 50 pence/min
To UK Mobile Vodafone 50 pence/min
To UK Guernsey/Jersey Mobile 65 pence/min
To UK Mobile Other 85 pence/min
To Landline 28 pence/min

and to Liechtenstein:
Call from Poland Mobile to Liechtenstein
To Mobile 65 pence/min
To Landline 30 pence/min

OK Estonia and Iceland mobile are cheaper - 50p :-)