Presidio is right next to my office, I had been to their information sessions are they are one of the very few in the world entirely dedicated for GREEN MBA. The plus points of this institute is
1) MBA structured just for sustainability
2) Location - San Francisco - home to major players in sustainability and high tech sector
3) They are not that expensive compared to other schools
4) Lots of young crowd waiting to jump into the field
On the flip side the cons I can think off is
1) Relatively new
2) Alumni is relatively small
3) Not tier1
So basically it all boils down to you
if your goal is to get into this field then presidio might not be a bad choice as they have good connections with the industry specific to their program, they encourage to start up your own business too.
But if your plan is to land up in a sure shot high paying job or to have a backup plan of shifting careers then better aim for the top 30 universities.
The way you can slowly transition to such a filed or increase your chances of getting into such a field is to get into social activites targeted for cleaner envrionment like
1) Cleaning up local parks/lakes/beaches
2) using cycle for work and joining a local cycle club.
3) Try influencing your local homeowners to shift to solar power, if you can say you made it possible at the rate of even 1 per month its a huge plus for your resume.
4) Start a blog on how you can make the world a better place in terms of promoting GREEN and post interesting articles you find all over the globe.
5) Start thinking how your technology background can actually help making this world more GREEN.
In this way you can slowly but surely build up your resume as a very strong candidate for your change in profession and shows how passionate you are.
And they are big school players slowly getting into this field like Haas - http://mba.haas.berkeley.edu/specialties_06.html
All said done, if you are very strong on this, write your GMAT this year in the next three months and then start building on your resume.
Even if you later change your mind the above said points will 500% help you in your application and most of the B-Schools prefer 3-4 years experience on an average.
Hope that helps. Let me know if you need any more information.