Hopefully a list of these additional countries will be released soon, but just know that the total countries that will have support for purchasing paid apps will quadruple at some point next week. Currently people in 32 countries can buy apps from Android Market, that number will increase by 99 when the changes are made.
During today's presentation on Android Market Eric Chu let it be know that 70% of daily new Android device activations are from outside of the USA, so this additional buyer support for Android Market has to be very welcome news to developers.
Google is also making changes to the 15 minute app refund policy, delaying the start of the countdown to download completion as opposed to the current at purchase practice.
Much more news will become available on these changes over the next few days. We will be checking the Android Developers blog for the promised blog post that should give further information on countries and availability.
We have some additional coverage of the Market changes here. (link expired)