Hi a new plugin for enlargements is available at mehdiplugins.com.
I've called it: "Quick Enlarger".
Quick Enlarger is a plugin for enlarging pictures with a better quality than the default resize tool from Photoshop (and almost any other retouching software of that kind). This is especially interesting to improve printings.
It has a proprietary interpolation algorithm "Crispy Zoom" to get breathtaking enlargements
More details here:
http://www.mehdiplugins.com/english/quickenlarger.htm
cheers
Mehdi