I've read in the help section that the edu license allows installs on two machines.
Do these two have to be the same OS, or could one be a Windows machine and one a Mac?
The Adobe product license agreement allows the primary user to install the product on a primary computer and also on a home or laptop computer for his or her use, provided that the two copies are not used simultaneously. However, CS6 products are platform specific, hence you will not be able to install on both the Platforms.
Jonathan, just a quick note to add — if you want to run the CS software on both Windows and Mac operating systems, then the new Creative Cloud for Education does allow installation of CS6 on both platforms (whereas the traditional licensing does not).