Does anybody know if Windows Phone 7.5 applications are going to be compatible with Windows Phone 8?
Thank you in advance
Yes, the existing applications will work on Windows Phone 8. However, Windows phone 8 apps will not work on Windows phone 7.5 (or 7.8).
Also keep in mind that you will not be able to upgrade your handset to Windows phone 8. To get the new OS, you will need to get a new phone.