This is Bengali keyboard program by Ermiyas inspired by Allan.

This package works with iOS4 and uses Winterboard file substitution.
After you install the package use Winterboard to apply Ermiy-Bangali theme, then apply the keyboard by going to Setting > General > Keyboard > International Keyboards > Add New Keyboard > Bulgarian > Bulgarian > Ermiy-Bengali then you should have the keyboard working. For more info please contact the author