1) Initial Google Checkout / Paypal purchasers
First of all you’ll have to convert your existing PZ details into a Desura key. These were emailed to you when you first bought the game (and are not your Indie Stone forum user/pass).
So simply fill out this form, and you’ll be well on your way: Indiedb.com
2) To find your Steam key on Desura
When logged onto Desura’s website, go to this page: Desura.com. Click on the ‘keys’ link, and you’ll find the Steam redeemable code listed there. You’ll be able to use this in the ‘Activate a product on Steam’ box that you’ll find in the Steam game menu.
Alternatively, you could just go here: Indiedb.com. Simple as that.
Our eternal thanks go to the good people of Desura for their help in this, and if you're not a Desura regular we implore you to check out their range of quality indie games.
Thanks! Good to have you back!