A new Allegro version is out that fixes a lot of stuff. I really recommend getting it, as it is the best version I've seen in a while. You can get an installer for it for Dev-C++, MSVC, or Borland at my page http://galileo.spaceports.com/~springs
My package use to only support Dev-C++ 4.x, but now it supports 5 too. In fact, you'll have to change the templates around a bit to support 4.x's Allegro templates... If you want 4.x templates, I would be happy to e-mail them to anyone who asks.
You can also get the source code distro from Allegro's hompage: http://sourceforge.net/projects/alleg/
Hope that helps those of you who use Allegro out there!