It seems like if you are a student or have an e-mail address that ends with .edu, you can order either a Home Premium or Professional Upgrade license for 29.99 plus tax until January 3, 2010.
Visit THIS WEBSITE and click on "BUY NOW $29.99".
They will first show a picture of Home Premium packaging, but you will have the option to choose Professional on the next screen.

I got more info:
1.What happens.
After you buy a license, you download a downloader first. The downloader didn't work unless I told my computer to RUN instead of SAVE the downloader when I downloaded the downloader.
Then you download one .exe file and 2 .box files using the downloader.
Click on the .exe file and the contests of the 2 .box files are unpacked into a new folder in the same directory.
Click on an setup.exe file inside the new folder to initiate installation.
2. Making an ISO file from so that you can make your own installation disk
In case someone downloads this, there's a way to make an
ISO file out of your download. I tried and could get a bootable
installation disk on my own.
Check THIS out.
3. One license per person under this program even if you have two computers.
4. If you order "their" installation disk for 13 dollars when you purchase a license through this program, you will get a 32-bit and 64-bit disks just like when you buy an upgrade package from a retail store, whereas you only get whichever you purchased if you make your own ISO and installation disk.
Core 2 Quad Q6600 2.4GHz, CORSAIR DOMINATOR 4GB (2 x 2GB) DDR2 1066 (PC2 8500), SAPPHIRE Radeon HD 4850, GIGABYTE GA-EP45-UD3P ATX, PC Power & Cooling S61EPS 610W, Western Digital Caviar Black 1TB HDDs, LG 22X SATA DVD Burner with LightScrib, Winodows 7 Professional x64, Antec 900 Case