The license is free/gratis (as in beer) for non-commerical/hobbyist use. You just join your local chapter of the DEC user group, and then register with HP (both can be done over the internet for people in the U.S.). This includes the Itanium license. The only caveat is that you will need to renew your license every year or your computer will effectively lock you out until you renew it. However, the renewal process is also free.
The difficulty as the OP noted is obtaining the install media. HP will sell you a OpenVMS/Itanium DVD for $500 (the DVD media, not the license to use it). Most people running OpenVMS on Itanium borrow the DVD from someone who has it, or who has access to it-- usually from work. These are not the type of people who put stuff up on torrent sites.
For the past two or three years, HP has been promising for it to be available through the Hobbyist program endorsed by HP, but run by volunteers. This group makes available CDrom media for installing OpenVMS on VAX and Alpha for the more reasonable cost of $30 including shipping anywhere in the world. Since the proceeds go to support the hobbyist org, and the license to use it is free, no one really minds spending this smaller amount on a CDrom.
Which is just to say that it's been an ongoing issue for people who want to run it on Itanium legally. If you can get your hands on the install media somehow, you can install it and run it legally. This is why the OP is asking around.
I too would be interested, and have been putting off purchasing an integrity rx2620 until it's released.