Thats what i use at the init :?

Code:
  // when texture area is small, bilinear filter the closest mipmap
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
  // when texture area is large, bilinear filter the original
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);