Irfanview then. Irfanview is freeware and will read *.psd (Adobe PhotoShop format) and *.psp (Paint Shop Pro format) files and save them to *.png (or several other formats).
This can be done either by opening each file and saving to the desired format or by taking advantage of IrfanView's Batch Conversion/Renam available under the File menu.
These are the file formats supported (before adding any plug-ins which add some more formats) -
This is the link to the Irfanview application itself -
I'd like to be able to convert psp and psd files to png files. I thought I could do that with GIMP, but can't seem to get it to happen. What would you recommend as the best FREE file converter(s) to use?