How to perform text extraction from images (screen-captures)

I'm new to PLP and so I've not had a chance to do an exhaustive search through all the components yet, but i was wondering if anybody knew how they would go about doing a text extraction from, say, a .png, or other screen-captured image? Are there any pre-existing components available to do this within PLP?
Otherwise it seems an area ripe for some Python incorporation (some good OCR libraries available).

Thanks,
Ben