Any suggestions on how that could be done. For example, an entertainment category could have PR3, PR2, PR1 and PR0 pages.
You can use this directory search to find free directories with PR greater than or equal to 3. You can also search by Traffic, price, deep links, niche, and a few other things. My advice is to search for PR then sort by Alexa Traffic Rating if you're interest in directories that might give you traffic.