Hello, I have released a plugin I'm working on that allows you to load XNB textures (compiled with the XNA Framework, version 4). For now it only supports texture loading, but in a future I'll add saving too, and more missing options (DXT textures, mipmap chains, Xbox format...).
Updated 06/28/2011:
v0.3.0.0 features:
Loads XNA 4 uncompressed Texture2D XNBs compiled for Windows or Windows Phone.
Supported pixel formats: Color, Bgr565, Bgra4444, Bgra5551.
New: loads Xbox assets.
New: supports formats Alpha8, DXT1, DXT3, DXT5.
Download v0.3.0.0 (current version):
PdnXnb_v0.3.0.0.zip
Download v0.1.0.0:
PdnXnb.zip
Project URL (includes source code):
http://pdnxnb.codeplex.com