If you are an existing DP8 user:
Download the Windows version and use the same keycode you were given at the time you purchased DP8. Your Mac install (if you have one) will remain activated, even after you activate your Windows install with the same keycode. Mac users should download the 8.02 Update for Mac.
If you want to try the 30-day demo (Mac or Windows)...
If you don't own DP8 yet and would like to try it, simply download the Mac version or Windows version of DP8, install it, and click Start Demo to begin your 30-day demo period. All features except MP3 exporting are available, including document saving. When your 30-day trial period ends, click Buy Now to purchase DP online, or you can purchase it from your favorite MOTU reseller.