InDesign CS6 is the last version that can open PM files. Results will be anywhere from good to nearly useless depending on the document. Make sure you unembed images and have all the links before you attempt to do the conversion.
If your RageMaker documents are at all complex, keep PM6.5 installed somewhere. There will be moments when you open up your PM document in ID, find that it's broken beyond repair, and want to open it up in PM to unembed images/recompose stories/break it up into smaller chunks/et cetera.