You can request to receive a CD by mail and
still download the software afterwards. I think anyone with access to mba.com can download their free stuff.
Here is the link to the PowerPrep:
http://www.mba.com/mba/TaketheGMAT/Tool ... ftware.htm
I recommend that you do the first test at the start of your preparation (this will give you an indiciation of where you stand). After you have studied a little, do the second test, but do it before you start with the Official Guide, because many questions overlap and your eventual score will be distorted. This is just my opinion - there are plenty of posts on this forum, where people smarter than me have shared alternative plans. Read some of those before you make any plans.
This is a link to the new version of the PP, called GMATPrep. It's fancier and marks the transition of the exam to a new test administration company (Pearson VUE).
http://www.mba.com/mba/TaketheGMAT/Limi ... ftware.htm
I haven't used this software yet, so I don't know if the questions overlap with the OG. Some people have mentioned that there are repeating questions.
The best piece of advice on my side: READ THIS FORUM AS MUCH AS YOU CAN!