unfortunately you have to pay a hefty price, go figure
TSN has the most available for ISS rankings as far as i know
Check out our monthly Future NHL Stars Report. It has the top 100 rankings and if you buy the online version, it's pretty reasonable, we think. Our Monthly Scouting Report is really geared toward hockey teams and agents. The Future Stars was created to make the information more affordable for hockey fans and poolies.
However, if that's out of your price range, your best bet is to get them off TSN. That's the most that is made available for free.