Axialis IconWorkshop permits you to create Windows® XP icons with smooth transparency. You can convert Macintosh® icons (up to OS-X) to Windows® format in a click! Create icons from PNG images with transparency or Photoshop® PSD images with layers!
AniSprite is an advanced high-performance sprite animation library for Microsoft Windows. Selected features are semi-transparent masks, alpha-channel mixing and automatic hit testing (collision detection). Full source code is available.