Hi Maria,
welcome to our forums! PRTools is a generic pattern recognition toolbox, not specific to OCR. So it won’t help you with skew correction or OCR-specific image preprocessing but might be useful for you to select/extract features and train/evaluate classifiers in your OCR problems.
If you have labeled data (extracted features for some observations like segmented letters, words, chunks of text) you can learn discriminants to label new examples automatically. Another field where it could be of interest is cluster analysis (if you want to see/identify the structures in your existing unlabeled data).
If you describe your problems in more detail, we can give you some more specific tips what methods to look at.
Best Regards,
Pavel