Hey i'm applying to Masters programs too but don't have a background in architecture so i may be talking out of my ass here but as long as you have a kick ass portfolio you have a chance of getting in. At least that seems to be the case from what i've gathered. You're "bad" GPA being 15 years old is probably beneficial if you can demonstrate increased effort recently (like ur recent 4.oo gpa!) It is probably best if you are up front about ur old gpa and address it in ur intent of purpose letter, just say you were disappointed with ur previous academic performance and look forward to challenging yourself in "the competitive environment that exist at harvard" or whatever.

MFE,

Thanks for the opinion. Good luck with your applications.

I cannot speak to your chances with those schools specifically, but I do think your background can work to your advantage. Grad schools are not just looking for students with undergrad degrees in architecture, nor are the just looking for people straight out of school. I think your previous experience in other fields combined with a portfolio and statement of purpose that ties everything together could really put you ahead of the typical student.

Good luck, like I said hard to know what your chances are...but I think that your past experience can only make you standout, which is a good thing.