I got Powernotes application for my 6630, but it`s an .app file. Can someone please tell me how can i get this file into my phone? Thx

u need 2 transfer that file to the folder where u installed the powernotes

An .app file is rearely the whole application, but just a part of it. Get the real/complete version as a .sis file and install it. If it is a commercial application, buy it from the shop:
http://www.allaboutsymbian.com/shop/